Hangs on Semop

Hello all!

I was just wondering if anyone else here has ever experienced Postgres
hanging on an INSERT or DELETE command?

Here is my setup:
DB:       Postgres 7.3.4
OS:      Fedora Core 1
Kernel:  2.4.22

The behavior is quite erratic. Using the exact same test script,
sometimes it runs and sometimes it hangs so it is rather difficult to
recreate the condition. We did an strace on postgres and got this:

postgres 14648  0.0  0.7 12524 4012 pts/2    S    03:30   0:00 postgres:
jug ubp [local] DELETE waiting

#strace -p 14648
Process 14648 attached - interrupt to quit
semop(851970, 0xbfe2bce0, 1

Nothing extraordinary shows up on the postgres logs itself.

Thanks for whatever help you can extend!