"System.IO.FileNotFoundException" in mscorlib.dll when loading standard .net class library

Each time I call a method in the class library a got the above mentioned exception. 

"dnx.exe" (CLR v4.0.30319: DefaultDomain): "C:\GitHub\CicConnector\wrap\ININ.IceLib-w64\..\..\lib\dnx451\ININ.IceLib-w64.dll" geladen. Symbole wurden geladen.
Ausnahme ausgelöst: "System.IO.FileNotFoundException" in mscorlib.dll

I'm using 1.0.0-beta8.

Any idea?