It's a little difficult to pinpoint the issue with the information provided, but I have a couple step that I think may help fix it.
First off, when you have a chance reset your Slingbox. This page: How to reset your Slingbox to factory settings shows you how. Often, set up issues will be fixed with a re-boot.
Once you have completed that, I'd recommend uninstalling and re-installing your SlingPlayer for iPad. This page, SlingPlayer for iPad Support has a link to the article that shows you how to do that.
Let me know if taking those steps fixes the issue.