What could be the reason behind a DBCC CheckDB reporting a consistency error on a empty table in sql server 2008? This DB is restored from sql server 2000. DBCC CheckDB on sql server 2000 doesnot report any errors.
It would be a lot easier if you post what error are you getting?
Usually the corruption was already there in the 2000 version but the latest and improved version of DBCC catches the errors that werent reported by the 2000 version of DBCC. Usually running DBCC UPDATEUSAGE might fix it and if the error doesnt go away you have to check what the specific error is and try to solve it accordingly. For all things CHECKDB i suggest you dig into all paul randal checkdb related blogs.
See the Remarks section of the documentation, which notes that a database upgraded from SQL2000 can give errors although there is no genuine error there.
SQL Server 2008's version of DBCC CHECKDB checks a lot more stuff that the SQL 2000 version. It is not uncommon for problems to be found in SQL 2008 that weren't found in SQL 2000. If I remember correctly CHECKDB on SQL 2005 runs DBCC CHECKCATALOG but the SQL 2000 version doesn't. Try running DBCC CHECKCATALOG on your SQL 2000 server and see if you get the error back.
In either case if you can post the error that you are getting from checkdb we can probably guide you to a resolution.