Thank you for using our answers forum! I'm sorry to hear you are having issues with adding your Slingbox to your account. We've noticed Internet Explorer does have some issues with our SlingPlayer Plug-in. If it is not allowing you to install the Plug-in, you are not out of luck. You could install another web browser to your PC if you have not already done so. I would recommend using Google Chrome. Once you have Google Chrome installed, go to setup.slingbox.com. It will prompt you to add the SlingPlayer Plug-in to Google Chrome. Which is much quicker than installing the Plug-in to Internet Explorer. It only takes about 1-2 minutes, at the most. After the Plug-in is added to chrome, it will take you right through the setup assistant that will add the Slingbox to your account. If you would not like to try Google Chrome, you could also try Mozilla Firefox. If you do not already have the Slingbox SOLO Quick Start Guide, here is a link that will take you to the download for it.
Hope this helps!
The Sling Moderation Team