Just saw your post in the MDM forums. Both Zinc and SWF Studio can capture the desktop contents but NOT once the screensaver has been started by Windows. You may THINK it's working while you are running the screensaver in test mode, but the security does not apply then.

You need a helper application to do this properly in all situations and the helper can't be launched by the screensaver, it has to be running in advance. You should also know that any kind of helper application like this should be considered a security hole and may not work in Vista because of new IPC (inter-process communication) security restrictions.