Postgres 7.2.2 Segment Error - Mailing list pgsql-hackers

I just saw this in my logs:

2002-09-18 12:13:10 ERROR:  cannot open segment 1 of relation users_sessions
(target block 1342198864): No such file or directory

This query caused it:

DELETE FROM users_sessions WHERE changed < ('now'::timestamp - '1440
minutes'::interval)  AND name = 'fhnid';

However, I cannot repeat the error now.  Is this a bug in postgres
somewhere.

Also, what should I do to fix the table properly.  I haven't vacuumed it or
anything yet in case someone wants to analyze it.

Chris