BUG #1684: ERROR: Relation 17065 does not exist

The following bug has been logged online:

Bug reference: 1684
Logged by: fremaux
Email address: benjamin.fremaux@sofrecom.com
PostgreSQL version: 7.2.2
Operating system: Linux kernel 2.4.6.19-mdk
Description: ERROR: Relation 17065 does not exist
Details:

Inserting data in a table I have the following message : "ERROR: Relation
17065 does not exist".
The database seems to be correct. I have rebuild many indexes because
problems like that appeared : "Index ind_name: NUMBER OF INDEX' TUPLES
(5020) IS NOT THE SAME AS HEAP' (5006)."

After doing that the same problem is going on. I do not know where to look
for.