I'm trying to attach FileWatcher eventhandlers dynamically to a Windows Service. However the code cracks with the following message:

Exception:
{"Object does not match target type." }

Code:
f = a.GetType("System.IO.FileSystemWatcher", true, true);
fw = Activator.CreateInstance(f);

//set the eventhandler
ei = f.GetEvent("Changed");
ei.AddEventHandler(f, new
 FileSystemEventHandler(FileListener.OnChanged));
ei = fw.GetType().GetEvent("Created");
ei.AddEventHandler(fw, new
 FileSystemEventHandler(FileListener.OnChanged));
ei = fw.GetType().GetEvent("Deleted");
ei.AddEventHandler(fw, new
 FileSystemEventHandler(FileListener.OnChanged));
ei = fw.GetType().GetEvent("Renamed");
ei.AddEventHandler(fw, new
 RenamedEventHandler(FileListener.OnRenamed));

Any suggestions?