The one suggestion that I would recommend trying, would be to try the new Desktop Slingplayer just released last month. Though it isn't technically supported for use with the Slingbox 500, I would recommend at least giving it a shot. Keep in mind though, that if it is not supported we cannot guarantee that it will work. Here is the link to download the new Desktop Slingplayer for your convenience:
Hope this helps!
Sling Media Forum Moderation Team