Just from Googling around it sounds like you might have installed a 64bit version of something that the login server is looking for a 32 bit version of:
http://msoos.wordpress.com/2010/09/1...rror-solution/
But it's odd that zone/world still work as they probably use much the same .DLLs (although I don't know what .DLLs the pre-compiled crypto library depends on).