I installed amember pro trial (zend version) and it seemed to install fine. I customised the templates and have no problems with that either. However when someone tries to signup, they get a 404 error. It's not the signup page but the page they are sent to when they click on continue. Any ideas why this might be happening? Thanks.
What is exact URL where it happens? Did you change "Secure Root URL" setting during setup? Check it at aMember CP -> Setup.