There is already a question with the same problem "Restoring SQL Server 2000 db to SQL Server 2005 db user issues" posted with a solution "I got it. It seems there is an order to things. I can now run the sp's either way. I don't have time to write it up but I will in case someone else runs into this issue."
But I can't find the solution in detail. How is it possible to get the solution.