strange domainname problem after upgrade 3.0 to 3.2

[mm]

hello,

after upgrading zentyal from version 3.0 to 3.2  on a vserver running ubuntu 12 lts, a really strange
problem came up. the domainname before the upgrade was like "stratoserver.net". well after
the upgrade it looks like this "stratoserver.net.stratoserver.net.stratoserver.net".
this destroys the dns lookup for my hosted domains on the server.

if i want to change the domainname in the general tab on the webinterface this warning comes up:

"WARNING: As the Users module is already installed and configured, if you change the hostname to
example.stratoserver.net.stratoserver.net you will LOSE ALL YOUR USERS DATA. Are you sure you want to continue?"

i manage a lot of users for mail only but if the above warning destroys all my user-db this would not be acceptable.

any help would be appreciated.