pg_dump: dumpBlobs(): error reading large object: ERROR:

Hi!

I could not able to take total backup of my database:

uname -a:
Linux mail 2.4.18-3 #1 Thu Apr 18 07:37:53 EDT 2002 i686 unknown


select version(); :
 PostgreSQL 7.2.1 on i686-pc-linux-gnu, compiled by GCC 2.96

pg_dump command:
pg_dump -d base -Fc -Z9 -b -v -f base.dmp 

pg_dump abort with this error:
pg_dump: dumpBlobs(): error reading large object: ERROR:  cannot read block
6389 of pg_largeobject_loid_pn_index: Input/output error

This error is caused by bad block on my  hard drive?

How can i do to recover database without lost blobs? Or to lose less
information?

Thanks,

Sergio Pili