diff --git a/lang/en_utf8/portfolio.php b/lang/en_utf8/portfolio.php
index 74d338cb1a6..8b4ef3d011a 100644
--- a/lang/en_utf8/portfolio.php
+++ b/lang/en_utf8/portfolio.php
@@ -76,6 +76,7 @@ $string['invalidtempid'] = 'Invalid export id. maybe it has expired';
 $string['invalidfileargument'] = 'Invalid file argument passed to portfolio_format_from_file - must be stored_file object';
 $string['invalidfileareaargs'] = 'Invalid file area arguments passed to set_file_and_format_data - must contain contextid, filearea and itemid';
 $string['invalidsha1file'] = 'Invalid call to get_sha1_file - either single or multifiles must be set';
+$string['invalidpreparepackagefile'] = 'Invalid call to prepare_package_file - either single or multifiles must be set';
 $string['invalidformat'] = 'Something is exporting an invalid format, $a';
 $string['invalidinstance'] = 'Could not find that portfolio instance';
 $string['invalidproperty'] = 'Could not find that property ($a->property of $a->class)';