MSN signing in problems

I'm not able to sign in on MSN when I'm using my router. If I'm just using the modem, everything works fine. I've tried everything I could think of and the suggestions from more than a few websites, and I've had no luck. I'm not sure if this is helpful or not, but when I do "REGSVR32 Gpkcsp.dll" in the cmd box, I get "LoadLibrary("Gpkcsp.dll") failed - The specified module could not be found." I'm getting the error 80048820 if it matters. Using windows XP pro by the way.