Newbie in connection trouble

Hi, i`m new to the world of firebird and i would like some advice from ppl who know what thay are doing.

So my problem:
I'm using Ubuntu 120.04 for my OS.
I installed firebird2.1-classic and flamerobin, then i connected to a given db without any problems.

But i turnes out the database i have to work with needs firebird 2.5.
So i purged the first installetion and installed firebird2.5-super, reconfigured the packedge.

Now when connectiong from isql-fb with no user and password supplied i get connected, but when i supply my user and password i get "cannot attach to password database".

From flamerobin when i register my server and try to view the servers version i get an other error "connection rejected by remote interface".

In the log file i get the following line:
"/usr/sbin/fbguard: /usr/sbin/fb_smp_server terminated due to startup error"

What i have allready tried:
1. Giving the path with and without 'localhost'
2. Checked the permissions on the db file.
3. Reisntalling the database several times.

I realy don't know what to do anymore.

Maybe i`m doing something realy wrong and sorry if my question is somehow stupid.

Thank you for any help in advence.