Error seen when vacuuming pg_largeobject table

Following a power fail restart, when I vacuum the pg_largeobject table I
see the following error messages:

VACUUM: DEBUG sql sql sql DEBUG: --Relation pg_largeobject-- blocks 450

VACUUM: DEBUG sql sql sql DEBUG: Pages 450: Changed 78, reaped 277,
Empty 0, New 37; Tup 1390: Vac 232, Keep/VTL 0/0, UnUsed 220, MinLen 98,
MaxLen 2092; Re-using: Free/Avail. Space 1464136/1463348;
EndEmpty/Avail. Pages 0/445.

VACUUM: CPU 0.05s/0.01u sec elapsed 0.56 sec.

VACUUM: DEBUG sql sql sql DEBUG: Index pg_largeobject_loid_pn_index:
Pages 14; Tuples 1044: Deleted 232.

VACUUM: CPU 0.00s/0.00u sec elapsed 0.00 sec. VACUUM: INFO sql sql sql
NOTICE: Index pg_largeobject_loid_pn_index: NUMBER OF INDEX' TUPLES
(1044) IS NOT THE SAME AS HEAP' (1390).

VACUUM: Recreate the index.

VACUUM: WARNING sql sql sql ERROR: Cannot insert a duplicate key into
unique index pg_largeobject_loid_pn_index

When I run postgres with the -P and -O options to reindex the index,
everything seem to run okay, I see no error messages. However, when I
restart postmaster and try and do a vacuum again, I get the same error
messages.

What can I do to correct the problem?

Thanks

Chris White