The likely problem is that you have not deployed the sapnco.dll (or an assembly that it depends on) in the correct place.
If your code is created as an IIS application, then you should deploy the assemblies to the bin subdirectory of your folder. If it is not an IIS application, then the assemblies should be deployed in the bin directory in the root of the web site. An alternative
option is to install the assemblies in the GAC
The Fusion Log Viewer tool can help diagnose these issues
Microsoft CRM MVP - http://mscrmuk.blogspot.com/ http://www.excitation.co.uk