I created a custom signup form. I chose a product that requires another product to already be purchased. Because I'm not logged in (I was testing), I got an error message. But there is no way, from there, to log in to fix the problem! I'd like to put a link under the error to the /login page, but editing _error.phtml seems to have no effect. Even after being successfully logged in, I still get an error on my signup page!
I tried adding %slogin%s to the error message in Edit Messages, but it just echos %slogin%s (on another message, it creates a login link)
Sorry but your post doesn't make sense really. Can you log in or not? One minute you say you cannot log in and next sentence 'Even after being successfully logged in ...' Plus you say you got an error message but give no indication what it is!! It might just give a clue as to what is going wrong. Can you log in as admin and delete the form? If you can log in as admin have you checked what the error log says? What core files have you changed apart from 'editing _error.phtml' Without some basic information there is no way anybody can help, sorry. Just saying you have an error message says nothing except that you have an error.