plpgsql PqReadData()

I am trying to set up a plpgsql function , when i tried to load it i
recieve this message

Postgresql 6.42 on Redhat 6.0

pqReadData() -- backend closed the channel unexpectedly.
This probably means the backend terminated abnormally before or
while processing the request.
We have lost the connection to the backend, so further processing is
impossible. Terminating.

Postmaster Debug shows

/usr/bin/postmaster: reaping dead processes...
/usr/bin/postmaster: CleanupProc: pid 27362 exited with status 139
/usr/bin/postmaster: CleanupProc: reinitializing shared memory and
semaphores

any Ideas

Thanks

gavin Stilgoe