Shahriar - 2013-10-04

Hello sir,
Whenever I tried to import an assembly I am getting the following error
check the image: http://www.mediafire.com/?g4xi01tswq74eb1

actually I want to create diagram for built-in class like SheelTile class etc, this class lies in the microsoft.phone.dll assembly. so I tried to open this dll and getting that error.

Need Help.
Thanks.