ORA-01595 and ORA-01594 upon startup

I have a database instance wich gives me the following error message everytime I restart it while doing my weekly cold backups:

Errors in file /disk1/app/oracle/admin/PWEB/bdump/pweb_smon_25704.trc: ORA-01595: error freeing extent (4) of rollback segment (5)) ORA-01594: attempt to wrap into rollback segment (5) extent (4) which is being freed

During the cold backup I:

1. shutdown immediate the database,
2. then startup restrict to get file names and then
3. shut it down immediate once more to actually copy the files and then
4. restart it.

When I do step b, I have the error in the alert log. I know it is only a warning, but I started getting this error when we recreated the database on a new machine. The only thing that chaged is the size of the rollback segments and the fact that they are now in a locally managed tablespace.

I recreated the rollback segments with their prior sizes, and I still get the error. I tried playing with the optimal size and got nothing useful.

I'm having a hard time figuring out what this message exactly means. Why would it wrap in a segment that is being freed ? There is still a huge amount of free space in the rollback segment. And I have almost NO transactions happening in the database at this time, it's late at night and I'm juste STARTING it. Received on Mon Feb 23 2004 - 12:28:48 CST