Problem creating a DB under 6.3.2 and Linux 2.00.33

Hi

ive compiled and installed postgres, did the initdb under
user postgres and so on. i think, there is nothing i didn't
pay attention to.
but when "createdb test" under user postgres or any other
user i get the  following brainsmashing error:

----------------
Connection to database 'template1' failed.
connectDBU() failed: Is the postmaster running and accepting
connections at 'UNIX Socket' on port '5432'?
createdb: database creation failed on test.
----------------

btw, postmaster IS running and listening on port 5432,
because i didnt change the port before compiling. so the
default port (5432) must be used by the postmaster - isnt
it?.

thnx for your attention
regards
stefan