Can't deploy Appx files topic

When i try to deploy a appx file, i got the following error
"The parameter is incorrect " and the installation aborts.
When i install xap's everything works fine.

My setup is Win7 Ultimate x64.
Deployment tool is the standart Windows Phone Application Deployment Tool ( 8.1 )
Target is a 1320 running on 8.1 pfd

If someone can shed some light on this issue............