This is a rather fun error. I have done some research and this is what I know so far:
1) The way to get this error is to start a 'long running' query and then have another user (or application) delete one (or more) of the objects that your query requires.
I'm confused because I can verify that no other user has modified the database AND that no other process has modified the database.
I have seen write errors on one of the scsi disks that some of the database files are on.
I have been able to successfully shut down the database and restart it.
Also I can run a query against one of the 'nonexistant' tables and it always fails at the same point.
I don't have access to the physical machine (this is part of my problem).
Assuming I can get the drive(s) in question to work properly (or replace them) what, if any, recourse do I have about objects that the database says no longer exist?
Not that it's a surprise but I don't have backups of this information (yet).
Any help is appreciated.