Yup - same here.:'(
It starts to run. I get a very brief window appears that states that there is already someone logged into my slingbox (yeah - me!) and then it crashes.
Looks like it's a problem with the Atrix, since you are getting the same thing. Hopefully SlingMedia will update this app.
I was having exactly the same problem. Decided to go ahead and hit that "Refund" button in the Market while it was still available. Maybe by the time we're actually getting "4G" speed out of this thing they'll have an updated app available.