Cannot add or delete mail accounts anymore..

[manos]

Fedora core 2.0 - Upgraded to Plesk 7.5.3. Installed isoqlog for qmail working properly. I cannot add or delete mail accounts anymore. Trying to do so browser stays busy (please wait loading graphic) for ever. Tried restarting all services, rebooted (both from plesk and terminal) but this did not solve the problem.
Any help will be greatly appreciated !!!

UPDATE: Problem solved !!! (by itself??)
I don't know how though. I changed ip address from shared to exclusive - it might be that.