Thank you for using our online answer forums. In order to better help resolve your issue, I would need to gather some more information. What exactly are you trying to install? Is it the plug-in or the old desk top player? Have you tried going to Setup.Slingbox.com to run through the configuration of your Slingbox?
Here are a few links you can try to troubleshoot your issue further?
Hope these help, feel free to replay with any other questions or concerns you are having!
The Sling Moderation Team