How to deal with corrupted database?

Hello all.

This is a first time I receive such an issue.
My database was corrupted some way.
When I'm trying to access the database via psql I receive:

root(at)udb:/etc/bacula# psql -U bacula
psql: FATAL: could not read block 0 in file "base/16387/86057840": read only 0 of 8192 bytes

So I want to drop it, and recover from backup. But when I'm trying to drop the database I see:

postgres=# drop database bacula;
ERROR: could not access status of transaction 15892843
DETAIL: Could not open file "pg_subtrans/00F2": No such file or directory.

Is there any way to recover the database to working state, or drop it?

OS: Linux Debian Sid
postgres version: 9.0.4
uname: Linux udb 2.6.32-5-xen-686 #1 SMP Tue Oct 19 17:09:04 UTC 2010 i686 GNU/Linux