cannot open source file "driver.tmh"的问题

用微软的UMDF Template例子遇到cannot open source file "driver.tmh"_问题.  微软的文章题目是:Write a UMDF driver based on a template, http://msdn.microsoft.com/en-us/library/windows/hardware/hh439659%28v=vs.85%29.aspx

不知道是何原因.
我的环境是:　WIN7 home preminum,  vs2012 trial, wdk 8.