diff --git a/code/model/DMSDocument.php b/code/model/DMSDocument.php
index 730911a..25522b2 100644
--- a/code/model/DMSDocument.php
+++ b/code/model/DMSDocument.php
@@ -808,7 +808,7 @@ class DMSDocument extends DataObject implements DMSDocumentInterface
 
         //write the filename of the stored document
         $this->Filename = $toFilename;
-        $this->Folder = $toFolder;
+        $this->Folder = strval($toFolder);
 
         $extension = pathinfo($this->Filename, PATHINFO_EXTENSION);