problems connecting to postgresql with unixodbc

Hello,

I'm running postgresql 7.0.3-4, on debian unstable, and I have trouble 
connecting to databases via odbc. I use unixodbc 2.0.3-1, and I can see
the data source in the DataManager, but when I try to connect I get the
following error:

'[unixODBC]Could not connect to the server;
Could not connect to remote socket.'

People have suggested to me that the problem might be that the
postmaster was not started with the -i option. I verified the postmaster.init 
file and
PGALLOWTCPIP=yes is set.

My pg_hba.conf file reads:

local        all                                           password
host         all         127.0.0.1     255.255.255.255     password


Can someone help me ?

Moritz