ad hoc installation error

Trying to install an app beta. The mobile provision file installs fine on my 64 bit Vista machine. The app itself appears to install fine and the icon appears in iTunes, but when I sync I get this error:

The application 'xxxxxx' was not installed on the iPhone 'Alli's iPhone' because an unknown error occurred (0xE8008015).

Anyone have any 开发者_如何学Pythonclues?

some information at http://blog.redfin.com/devblog/2009/09/installing_beta_builds_on_iphone.html and google has lots of hits: