psql error: could not connect to server

Hi list,

I just downloaded the source from PostgreSQL 7.4.1 and installed it on Red
Hat 9. Install was succesfull. After this I installed PostGIS 0.8.0.

To test the PostGIS install I need the perform the following command:

createlang plpgsql postgistest

But on performing this I get the following error:

psql: could not connect to server: No such file or directory
        Is the server running locally and accepting
        connections on Unix domain socket "/tmp/.s.PGSQL.5432"?
createlang: external error

Anybody have an idea what could be the problem?

Thanks in advance!

Best regards,
Bart