You need to run
omnidbcheck -extended
to identify which part of the IDB is corrupted
Unfortunately, this is probably not a problem that can be solved in the Forums, you will need to open a new case with DP support. I know that I have a case with identical symptoms that is currently unresolved
Unless there is something about DP 8 that you really need, you should probably think about going back to DP 7, if you have a backup, either on tape, or a saved 'db40' directory