You picked it up from the Amazon email to your PE? It should install with no problem once you check the box allowing "unknown sources" (settings/manage applications).
If you mean you have it properly installed and it is misbehaving, my first question is did it ever work for you? Does Amazon have your device listed as unknown edgejr?
Are you running the Dingo build, or did you upgrade to Ermine? The appstore should work with either, I think, unless the most recent appstore app update made it not work with Dingo. Anyone else having problems??
Welcome to the eDGe community on MobileRead!
Don't know that I've been much help, but I want you to know that there is hope! I got that message a few times and found a fix. Just wish I could remember exactly what it was!