Sometimes classes are seperated i different assemblies and you need to load classes from a specific assembly. Here is a way to load a class and instanciate a variable of that type:

try {
System.Runtime.Remoting.ObjectHandle objHandle =
System.Activator.CreateInstanceFrom(Application.StartupPath + @”\MyAssembly.exe”, @”MyNameSpace.” + @”MyClassName”);
} catch(TypeLoadException) {
// Problems loading class
}

if(objHandle != null) [...]