newbie problem on creating table

I am trying to get a start with Postgres 6.4 on Suse Linux 6.4. I created a
superuser who is allowed to create databases. I created a user and a
database, but I didn't manage so far to create a table. It just returns
"Error cannot create .
In the configuration file for the authentication, I used the settings coming
with the installation:

local all            trust
hosts all 127.0.0.1 255.255.255.255 trust

The logfile also just shows the messages:
Error: Cannot create 
AbortCurrentTx
....

I am really stuck and have no glue where to look or to start. Any help is
highly welcome

thomas

PS: posted to pgsql-novice and pgsql-general