Corruption on production system

We've got a PG 7.3.6 installation that just started receiving this
error:
2005-04-25 19:28:54 ERROR: Invalid page header in block 1110 of
the_table_name

We're also unable to dump that table using pg_dump. Postgres isn't
actually crashing, so I'm not sure how to get a backtrace out of it.

SELECT version():
PostgreSQL 7.3.6 on i686-pc-linux-gnu, compiled by GCC gcc
(GCC) 3.3.2 20031218 (Gentoo Linux 3.3.2-r5, propolice-3.3-7)

(Don't get upset that it says Gentoo -- I built it myself from
official Postgres sources)

Is page header corruption a known issue with 7.3.6 and should I
upgrade to 7.3.9 at the same time that I'm restoring this table from
backup?

Any quick advice will be greatly appreciated!

thanks

eric