I faced The Below Problem Few Days Back With The follwing Error .
"Could not resolve mscorlib for target framework '.NETFramework,Version=v4.0'. This can happen if the target framework is not installed or if the framework moniker is incorrectly formatted."
Build Failed Without Errror Description
As I as Using XP It was MAX_PATH I just Kept the Path below "240".
The path Should be Under "256 Character".
That Solved It.
Hope It Help Somebody.