Pgdump error "invalid page header in block"

Yesterday, I had some problem with postgresql 9.0.2. Today i backup postgres and has error

pg_dump: reading dependency data
pg_dump: SQL command failed
pg_dump: Error message from server: ERROR:  invalid page header in block 299 of relation "pg_depend_depender_index"
pg_dump: The command was: SELECT classid, objid, refclassid, refobjid, deptype FROM pg_depend WHERE deptype != 'p' ORDER BY 1,2
pg_dump: *** aborted because of error

Is there any way to fix it.

Thanks in advance

Tuan Hoang ANh