I ran into a interesting exception yesterday when trying to run NServiceBus on Windows 7 with Visual Studio 2010 Beta 2
System.NotSupportedException: An attempt was made to load an assembly from a network location which would have caused the assembly to be sandboxed in previous versions of the .NET Framework. This release of the .NET Framework does not enable CAS policy by default, so this load may be dangerous. If this load is not intended to sandbox the assembly, please enable the loadFromRemoteSources switch. See http://go.microsoft.com/fwlink/?LinkId=131738 for more information.
I found some more info on this blog.
Basically the fix is to add the following to your App.Config
<runtime> <loadFromRemoteSources enabled="true"/> </runtime>