pg_dump error

I have recently upgraded to postgresql 7.2.
When I try to take backup with pg_dump, one of the database is
generating
the following error.

pg_dump: query to obtain procedure name for trigger
"ins_extranet_cspm_bug" did not return exactly one result

I checked the  for the trigger "ins_extranet_cspm_bug"  from
pg_trigger system catalog table, it is retrieving just one error.
What is the cause of this error and how can I fix it. We are planning
to upgrade
database to postgresql7.2 from 7.1.3 in this week. But now I'm scared
to do it in production with this problem.
Thanks for any help
chava