As per Jon’s reply, it would be helpful to know what’s in LoaderExceptions. In lieu of this information, I think I can hazard a guess. From MSDN:
If the assembly has dependencies, the
ReflectionOnlyLoad method does not
load them. If you need to examine
them, you must load them yourself.
You need to attach a handler to AppDomain.ReflectionOnlyAssemblyResolve to help the CLR load any dependencies of the assembly you’re loading. Have you done this?