After Update to 6.20.Rev5 Login Screen Error invalid i18n

[ms75]

Hi,
today i have made the update on my debian squezze to version 6.20.6. After a restart of the services i could login with an admin account and everything worked. But when i now open the login page in the browser an error button appears with the text Invalid i18n for id="d28e155". I have cleared the Browser cache an tried other browsers but nothing worked. I can quit the message with the button Ok but then the loading circle is only visible and the form fields for entering the login credentials never appears...
Dou you have an clue what happend - in the logs i could't see anything.
Thanks.

Edit: Sorry, update is to version 6.20.6

[ms75]

I have made a reinstall and now it works again... don't know what has happened on the first install, maybe something was broken...