INTERNAL SERVER ERROR when accessing Domain-Details

==== Required information ====
- iRedMail version: 1.8.2
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): iRedAdmin-Pro-MySQL
- Linux/BSD distribution name and version: Ubuntu 12.04.4 LTS
- Related log if you're reporting an issue:
====

I upgraded my 1.8.1 Version to 1.8.2

But when I log on to iredAdmin Domains and Accounts-> Edit account profile I get "internal server error", Domain activities etc. seems to be working fine.

Someone else had this issue with 1.8.1 and it was fixed by upgrading to 1.8.2. But i am running 1.8.2, this Version is shown in my Licence-Area.

Any Ideas?

Thanks in advance!
Carsten