Is the Mismatch between the Procedure name that SQL has on the error, and the actual assembly name a problem?

Are you running SQL Server as an account that has permission to access the DLL / Local File System?

If this is a .NET Assembly, are all the CAS permissions set properly on the server and in the application? I have tried to run assemblies before and the OS thinks they are in the InternetZone (because I dragged and dropped the file and did not copy and paste) and does not give them permission to run (moved files do not inherit thier parent objects permissions!). Try Taking Ownership or resetting the permissions on the file (and in CAS / .NET config admin) and see if it works.