broken link upon filling out buddypress registration

[newatthis]

Hi! I have S2 installed using buddypress, had a test member join, paypal redirected to the buddypress registration page, which they filled out with username, password, about me, etc, but then when they went and clicked the 'complete sign up' button, it redirected to an error page that stated that the link appears to be broken. Does anyone have any idea why it is not redirecting to the home page or website??? Anyone how know to fix this??? ANY help would be greatly appreciated!!!! Thanks!