error in postgresql

pls check for the error and tell me if any solution can be come upon.
TIA
Sharmad
Script started on Tue Oct 30 10:24:36 2001
postgres@linux:~ > pg_dumpall > alllms_30-10-2001.bak
SQL query to dump the contents of Table 'common_to_three' did not execute.  Explanation from backend: 'pqReadData() --
backendclosed the channel unexpectedly. 
    This probably means the backend terminated abnormally
    before or while processing the request.
'.
The query was: 'COPY "common_to_three" TO stdout;
'.
pg_dump failed on lms, exiting
postgres@linux:~ >
Script done on Tue Oct 30 10:24:48 2001