Website can't refer to correct location

Environment: Windows Server 2003 Enterprise X86 + Framework2.0 + IIS6.0 + Cluster Issue: 1.For website normal working, I must copy System.Data.OracleClient.dll to Bin folder.              However, that dll is standard. Why do I still need to do this?           2.My website have a web.config that put in root(virtual) folder, but the path in run-time is appointed to framework folder.              That made my website not working.   I don't want to copy standard dll to bin folder nor want to appoint path in my code. I think that  my environment have some issue, so how to do something to make website normal working, can anyone help me?