It sounds like you are not using exactly the same username that your using on the server.  For instance, you might be using sa on the server and windows authentication...

Have you tried using sp_changedbowner to change it back to the senior developer? 

Incidentally you can use sp_changeobjectowner to change any tables, view etc, back to dbo.

I had indexes on all my where conditions, and they were all on numeric columns, (so no problem with collation).  SQL Server used the indexes on oracle for the select statements but not for...