Attempted to read or write protected memory. This is often an indication that other memory is corrupt.

http://social.msdn.microsoft.com/Forums/en-US/vbpowerpacks/thread/8789ea67-fbc5-4a7b-a4eb-d4a8a050d5c1

http://social.msdn.microsoft.com/Forums/en-US/csharpgeneral/thread/4f48c152-68cd-45ec-a11e-baa7de7f79c3