I can see that you're having problems with the Web Based SlingPlayer.
In this case, and as a first step, I would recommend to check if you can get it to work properly, with Safari running 64-Bit mode.
To enable the 64-Bit, you can check the following link:
Also, you can unistal the plug-in and download it back.
Besides that, try using a different browser such as Google Chrome or Firefox.
If the problem is still the same, try to connect to the Slingbox with the computer hardwired to the router, and discard any restriction preventing the Slingbox to work.
You can also, post the results here.