Ensure proper type of argument

public/typo3conf/ext/ep_theme/Classes/Controller/FormController.php

@@ -69,7 +69,7 @@ class FormController extends ActionController
         return $this->uriBuilder
             ->reset()
             ->setCreateAbsoluteUri(true)
-            ->setTargetPageUid($pageUid)
+            ->setTargetPageUid((int)$pageUid)
             ->build()
         ;
     }