If the metadata is corrupt, you're not going to be able to drop the index, no matter what commands you try.
Before trying any more shotgun approaches...
Do you have a backup of this database? Do you have log backups?
What's the downtime and data loss allowances for this database?
How big is that table? (rows/MB)
When was the last time you ran an integrity check that came back clean?
Can you run the following statement and post the full and complete, unedited output?
DBCC CheckCatalog('elmah') with no_infomsgs
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