diff --git a/src/server/i18n/de.php b/src/server/i18n/de.php
index 8fb4493..231f2a3 100644
--- a/src/server/i18n/de.php
+++ b/src/server/i18n/de.php
@@ -4,6 +4,9 @@ $i18n = array(
     'error.noJavaScript' => 'Bitte aktivieren Sie JavaScript in den Einstellungen Ihres Browser um diese Seite verwenden zu können.',
     'error.browserNotSupported' => 'Ihr Browser wird nicht unterstützt. Bitte verwenden Sie einen aktuellen Browser.',
     'error.errorLogged' => 'Es ist ein Fehler aufgetreten. Bitte prüfen Sie die Log-Datei.',
+    'error.editingArticleFailed' => 'Der Artikel kann nicht bearbeitet werden.',
+    'error.missingWritePermissions.article' => 'Der Server hat keine Schreibrechte für die Artikel-Datei:',
+    'error.missingWritePermissions.backup' => 'Der Server hat keine Schreibrechte für die Backup-Datei:',
     'button.cancel' => 'Abbrechen',
     'button.back' => 'Zurück',
     'button.edit' => 'Bearbeiten',
diff --git a/src/server/i18n/en.php b/src/server/i18n/en.php
index 3a59185..6534774 100644
--- a/src/server/i18n/en.php
+++ b/src/server/i18n/en.php
@@ -4,6 +4,9 @@ $i18n = array(
     'error.noJavaScript' => 'Please activate JavaScript in the settings of your browser in order to use this site.',
     'error.browserNotSupported' => 'Your browser is not supported. Please use an up-to-date browser.',
     'error.errorLogged' => 'An error has occurred. Please have a look to the log file.',
+    'error.editingArticleFailed' => 'Editing article failed.',
+    'error.missingWritePermissions.article' => 'The server has no write permissions for the article file:',
+    'error.missingWritePermissions.backup' => 'The server has no write permissions for the backup file:',
     'button.cancel' => 'Cancel',
     'button.back' => 'Back',
     'button.edit' => 'Edit',
diff --git a/src/server/layout/page.php b/src/server/layout/page.php
index c816655..904449d 100644
--- a/src/server/layout/page.php
+++ b/src/server/layout/page.php
@@ -61,19 +61,24 @@ $mode = $data['mode'];
 if ($mode != 'view') {
   // Show an error message if JavaScript is off or if the browser is not supported.
   // NOTE: In view mode we don't show an error. Instead, syntax highlighting will be off for unsupported browsers.
-  ?><div id="fatal-error-message"><div><?php echo $i18n['error.noJavaScript']; ?></div><a class="btn btn-default" href="<?php echo $data['requestPath']; ?>"><?php echo $i18n['button.back']; ?></a></div>
-  <script type="text/javascript">
-    (function() {
-      var errElem = document.getElementById('fatal-error-message');
-      if (slimwiki.supportedBrowser) {
-        errElem.parentNode.removeChild(errElem);
-      } else {
-        errElem.firstChild.innerHTML = <?php echo json_encode($i18n['error.browserNotSupported']); ?>;
-      }
-    })();
-  </script>
-  <div id="error-alert"><div class="alert alert-warning"><?php echo $i18n['error.errorLogged']; ?></div></div>
+  ?><div id="fatal-error-message"><div><?php echo ($mode == 'error') ? $data['fatalErrorMessage'] : $i18n['error.noJavaScript']; ?></div>
+    <a class="btn btn-default" href="<?php echo $data['requestPath']; ?>"><?php echo $i18n['button.back']; ?></a>
+  </div><?php
+
+  if ($mode != 'error') { ?>
+    <script type="text/javascript">
+      (function() {
+        var errElem = document.getElementById('fatal-error-message');
+        if (slimwiki.supportedBrowser) {
+          errElem.parentNode.removeChild(errElem);
+        } else {
+          errElem.firstChild.innerHTML = <?php echo json_encode($i18n['error.browserNotSupported']); ?>;
+        }
+      })();
+    </script>
+    <div id="error-alert"><div class="alert alert-warning"><?php echo $i18n['error.errorLogged']; ?></div></div>
   <?php
+  }
 }
 
 if ($mode == 'edit') {
@@ -151,7 +156,7 @@ if ($mode == 'edit') {
 
 ?></div><?php // id="main-wrapper" ?>
 
-<?php if ($mode != 'view') { ?>
+<?php if ($mode == 'edit' || $mode == 'createUser') { ?>
 <!-- build:js client/edit.js -->
 <script src="client/libs/CodeMirror/lib/codemirror.js"></script>
 <script src="client/libs/CodeMirror/addon/mode/overlay.js"></script> <!-- Allow language-in-language -->
@@ -169,13 +174,15 @@ if ($mode == 'edit') {
 
 <script src="client/js/app-edit.js"></script>
 <!-- endbuild -->
-<?php } // if ($mode != 'view') ?>
+<?php } // if ($mode == 'edit' || $mode == 'createUser') ?>
 
+<?php if ($mode != 'error') { ?>
 <!-- build:js client/view.js -->
 <script src="client/libs/highlightjs/highlight.pack.js"></script>
 
 <script src="client/js/app-view.js"></script>
 <!-- endbuild -->
+<?php } // if ($mode != 'error') ?>
 
 </body>
 </html>
diff --git a/src/server/logic/EditorService.php b/src/server/logic/EditorService.php
index a9b3fef..2a41bfe 100644
--- a/src/server/logic/EditorService.php
+++ b/src/server/logic/EditorService.php
@@ -36,6 +36,32 @@ class EditorService {
         }
     }
 
+    public function checkForError($articleFilename) {
+        function canWriteFileOrParent($filename) {
+            if ($filename == '') {
+                return false;
+            } else if (file_exists($filename)) {
+                return is_writable($filename);
+            } else {
+                return canWriteFileOrParent(dirname($filename));
+            }
+        }
+
+        $articleFullFilename = $this->context->getArticleBaseDir() . $articleFilename;
+        if (! canWriteFileOrParent($articleFullFilename)) {
+            return $this->context->getI18n()['error.missingWritePermissions.article']
+                . ' <code>' . $articleFullFilename . '</code>';
+        }
+
+        $backupFullFilename = $this->context->getDataBaseDir() . $this->getBackupFilename($articleFilename);
+        if (! canWriteFileOrParent($backupFullFilename)) {
+            return $this->context->getI18n()['error.missingWritePermissions.backup']
+                . ' <code>' . $backupFullFilename . '</code>';
+        }
+
+        return null;
+    }
+
     public function saveArticle($articleFilename, $markdownText) {
         $this->assertLoggedIn();
 
@@ -43,23 +69,26 @@ class EditorService {
             throw new Exception("Invalid article filename: '$articleFilename'");
         }
 
-        // Set timezone
-        $this->context->getConfig();
-
         // Write article file
         $articleFullFilename = $this->context->getArticleBaseDir() . $articleFilename;
         $articleDir = dirname($articleFullFilename);
         if (! file_exists($articleDir)) {
             mkdir($articleDir, 0777, true);
         }
+        if (! is_writable(file_exists($articleFullFilename) ? $articleFullFilename : $articleDir)) {
+            throw new Exception("No write permissions for article file");
+        }
         file_put_contents($articleFullFilename, $markdownText);
 
         // Write backup file (one per day)
-        $backupFullFilename = $this->context->getDataBaseDir() . 'backup/' . $articleFilename . date('_Y-m-d') . '.gz';
+        $backupFullFilename = $this->context->getDataBaseDir() . $this->getBackupFilename($articleFilename);
         $backupDir = dirname($backupFullFilename);
         if (! file_exists($backupDir)) {
             mkdir($backupDir, 0777, true);
         }
+        if (! is_writable(file_exists($backupFullFilename) ? $backupFullFilename : $backupDir)) {
+            throw new Exception("No write permissions for backup file");
+        }
         $fp = gzopen ($backupFullFilename, 'w9');
         gzwrite ($fp, $markdownText);
         gzclose($fp);
@@ -67,6 +96,13 @@ class EditorService {
         return $this->context->getRenderService()->renderMarkdown($markdownText, true);
     }
 
+    private function getBackupFilename($articleFilename) {
+        // Set timezone
+        $this->context->getConfig();
+
+        return 'backup/' . $articleFilename . date('_Y-m-d') . '.gz';
+    }
+
     public function createUserConfig($user, $pass) {
         $type = 'sha256';
         $salt = uniqid(mt_rand(), true);
diff --git a/src/server/logic/Main.php b/src/server/logic/Main.php
index 3e9c04d..cb9026d 100644
--- a/src/server/logic/Main.php
+++ b/src/server/logic/Main.php
@@ -58,8 +58,8 @@ class Main {
                     try {
                         $responseData['result'] = call_user_func_array(array($object, $methodName), $requestData['params']);
                     } catch (Exception $exc) {
-                        $msg = "Calling RPC $objectName.$methodName failed";
-                        error_log($msg . ': ' . $exc->getMessage());
+                        $msg = "Calling RPC $objectName.$methodName failed: " . $exc->getMessage();
+                        error_log($msg);
                         $responseData['error'] = array( 'code' => -32000, 'message' => $msg );
                     }
                 }
@@ -102,10 +102,20 @@ class Main {
         } else {
             $config = $this->context->getConfig();
 
+            $fatalErrorMessage = null;
+            if ($mode == 'edit') {
+                $fatalErrorMessage = $this->context->getEditorService()->checkForError($articleFilename);
+                if ($fatalErrorMessage != null) {
+                    $fatalErrorMessage = $this->context->getI18n()['error.editingArticleFailed'] . '<br/>' . $fatalErrorMessage;
+                    $mode = 'error';
+                }
+            }
+
             $data = array();
             $data['baseUrl']    = $baseUrl;
             $data['basePath']   = $basePath;
             $data['mode'] = $mode;
+            $data['fatalErrorMessage'] = $fatalErrorMessage;
 
             foreach (array('wikiName', 'footerHtml') as $key) {
                 $data[$key] = $config[$key];