missing pg_clog files ?

There was a thread on missing pg_clog files caused due to dodgy practices in
glibc *last year*. I am seeing something similar *now* with a server

PostgreSQL 7.4beta1 on i386-unknown-netbsdelf1.6X, compiled by GCC 2.95.3

accessed by a similar client and a client

PostgreSQL 7.4devel on i686-pc-linux-gnu, compiled by GCC 2.95.4

The following works:

select * from olddata02_03vac offset 2573718 limit 1;

however

select * from olddata02_03vac offset 2573719 limit 1;
ERROR: could not access status of transaction 1664158221
DETAIL: open of file "/usr/local/pgsql/data/pg_clog/0633" failed: No such file or directory

and

# ls -l pg_clog
total 32
-rw------- 1 postgres postgres 16384 Sep 22 13:12 0000
#

Is it true that the problem was with the server, so the fact that a glibc
client was connecting and possibly doing a vacuum is irrelevant?

What can I do now to fix it? Known problem with beta1 which is now old?

Cheers,

Patrick