diff --git a/h5p.classes.php b/h5p.classes.php
index 1fe5140..ec363f0 100644
--- a/h5p.classes.php
+++ b/h5p.classes.php
@@ -1610,7 +1610,9 @@ Class H5PExport {
     foreach ($files as $file) {
       // Please note that the zip format has no concept of folders, we must
       // use forward slashes to separate our directories.
-      $zip->addFile(realpath($file->absolutePath), $file->relativePath);
+      if (file_exists(realpath($file->absolutePath))) {
+        $zip->addFile(realpath($file->absolutePath), $file->relativePath);
+      }
     }
 
     // Close zip and remove tmp dir