Are you using diskeeper?
I suspect you're running into this issue. Please check what disk utilities you have installed.
http://blogs.msdn.com/b/psssql/archive/2010/01/08/dbcc-check-commands-encounter-problems-and-reports-errors.aspx
http://sqlblog.com/blogs/jonathan_kehayias/archive/2009/12/10/a-tale-of-checkdb-failures-cause-by-3rd-party-file-system-drivers.aspx
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability
We walk in the dark places no others will enter
We stand on the bridge and no one may pass