ERROR: could not access status transaction #####

Dear,

I would like to call on your assistance with regards to the following error
I'm receiving in a PostgreSQL database:

When creating new objects in PostgreSQL, after queries or when a VACUUM is
launched the following error appears:

ERROR: could not access status transaction #####
DETAIL: could not open file : pg_clog/#### : No such file or directory

The error started to appear after I ran out of disk space on the partition
where PostgreSQL is installed.

Actions already taken:
+ Creation of zero (/dev/zero) files for each missing file

I don't have a dump available from before the incident, but I have a dump
from each table. As PostgreSQL is hosting 400GB, I was hoping to avoid a
complete restore.

Any assistance on how to solve this issue would be appreciated.

This concerns:
PostgreSQL 8.1.1 running on RHE4 (64-bit)

Kindest regards,
Jorge