addpackageasync attempted to reference a token that does not exist (Error Code 0x800703F0)

I'm currently trying to build a company hub for WindowsPhone 8.1. So I made the AET and registered as a Company in the Dev Center. Now I have a problem by calling the InstallationManager.AddPackageAsync() method. It gives me the Error in the title:

addpackageasync an attemp was made to reference a token that does not exist (Error Code 0x800703F0)

but I can install apps via InternetExplorer or E-Mail.

Has anyone an idea?

Thanks in advance Patrick