Just FYI - if you are using the System.Net.OracleClient namespace with 10g it is possible you will run into this error. Now before you start getting too excited about being able to set the ReturnProviderSpecificTypes property on an adapter, you can run into this problem with output parameters on an ExecuteNonQuery so it's probably a safer bet to use the OleDb provider with 10g.
Flame on if I'm wrong.
