It seems that you are having some issues since you are not able to keep a steady connection to your Slingbox PRO HD.
I recommend you contact someone at the Slingbox location and reset the Slingbox. Once you reset it, you will run the Setup Assistant for Internet Viewing. This process will allow you to get rid of any network-related error.
The following links will allow you to get some articles that could help you to fix this issue.