diff --git a/mod/resource/lib.php b/mod/resource/lib.php
index 96e0c42cecf..b947b51fa10 100644
--- a/mod/resource/lib.php
+++ b/mod/resource/lib.php
@@ -385,7 +385,7 @@ function resource_pluginfile($course, $cm, $context, $filearea, $args, $forcedow
     $relativepath = implode('/', $args);
     $fullpath = "/$context->id/mod_resource/$filearea/0/$relativepath";
     if (!$file = $fs->get_file_by_hash(sha1($fullpath)) or $file->is_directory()) {
-        $resource = $DB->get_record('resource', array('id'=>$cminfo->instance), 'id, legacyfiles', MUST_EXIST);
+        $resource = $DB->get_record('resource', array('id'=>$cm->instance), 'id, legacyfiles', MUST_EXIST);
         if ($resource->legacyfiles != RESOURCELIB_LEGACYFILES_ACTIVE) {
             return false;
         }