Hi,
This may have something to do with new behavior of the DBCC CHECKDB, which creates internal snapshot of the database. To disable snapshot creation, specify WITH TABLOCK option, but then you will have locking on tables, like you had in SQL 2000.
How do you connect to the database you want to DBCC? Do you use EXECUTE AS/REVERT?
Regards
Piotr
...and your only reply is slàinte mhath