System.Collections error while building the player for windows phone 8

Hi
I am getting this error while building the player for Windows Phone 8. The error come during Postprocessing Player

Error building Player: Exception:
Error: type System.Collections.Specialized.NameValueCollection doesn’t exist in target framework.
Error: type System.Collections.Specialized.NameObjectCollectionBase doesn’t exist in target framework.

The error is repeated uncountable number of times.
Someone please help me out with this.

remove the Plugins that are not used for Windows phone 8 Build
That will mostly solve this issue. .