Sounds like the WMP control used by netflix is over the top of the screen saver in the background. Whurlston, there are APIs on the PluginHelper to disable and reenable the screen saver.
The activeX control does disable the screensaver whenever playback is started. It enables it back whenever the playback is paused or stopped. I'll double check to make sure that it gets disabled when playback is resumed as well but I'm pretty sure it does.