error while hitting button 'upload' (login script)

In order to create an alias/shortcut for a user to his network homedrive I'm trying to upload a login script.

Under Profile Manager > Login > Scripts > Login script, I want to upload a script but when I hit the "upload"-button I get this error (translation from Dutch to English):

There has been an error

Reload Profile Manager en try again

Error: TypeError: 'undefined' is not a function (evaluating 'target.tryToPerform(action,sender)')

This error keeps re-occuring when I try to upload a script.