I understand that you are having some issues with the Slingbox when running the connection through your computer.
The fact that you are able to get the connection on your iPad means that the Slingbox is a helpful unit. In this case, the issue seems to be related to your computer. As a workaround, I recommend you to test the connection from a different computer.
This test will allow you to verify if the issue is related to any (security) setting on your computer.