Segmentatin fault on starting up psql

Versions:
Occurred in postgreSQL 6.5.3-7 and 7.0-3 (both rpm installs) and also in
7.0.2 (compiled from source)
OS: Redhat Linux 5.2, with many upgraded components
System: Cyrix i686 PR233

After I create a database, I tried to use psql to add the entries.
However, on activating psql, I get a segmentation fault. This is the
error message that postmaster generated.

pq_recvbuf: unexpected EOF on client connection


What could have gone wrong? I spend the whole day fighting with it with
the three different versions above.

Thanx in advance
Ryan