pqReadData() -- backend closed the channel unexpectedly.

Hi All,

When I give the attached function, i get this error :

"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.  "

Does someone explain me why?
Thanks in Advance
Regards
Ismail Kizir