Thanks for posting in the forums! I'm sorry to hear you are unable to stream via pop-up player. Just to verify, do you have a pop-up blocker on your PC? Also, what web browser is it that you are using on your PC?
I would recommend trying another browser, to see if that resolves the issue. It does not seem to be an issue with the Slingbox, but more of an issue with the browser or your PC.
If you are using Internet Explorer; below is a link to an article from our knowledgebase that may explain why you're experiencing this issue:
Feel free to reply!
The Sling Moderation Team