Error on pg_dump

Hello,

I have postgres 7.4.1-3 on cygwin... Everytime, when I try to dump data,
pg_dump raise error:

pg_dump: SQL command to dump the contents of table
"l_image_to_round_trip" failed
pg_dump: Error message from server: server closed the connection
unexpectedly
This probably means the server terminated abnormally
before or while processing the request.
pg_dump: The command was: COPY public.l_image_to_round_trip (i_image_id,
i_round_trip_id)
TO stdout;
pg_dumpall: pg_dump failed on database "medina", exiting

table in error sometimes changes... I try to, create new data direcotory
with dbinit, but without changes...

PS: Why there is no postgres 7.4.2 in cygwin mirrors???

thanx, miso