I've done this two different ways before. The first way is to sign up for Asiana club, then you can log-in with your OZ confirmation number and membership number.
The other way is to use the 005 eticket number. For this case, remove the default 988 number in the "Guest Access" part and then paste in your full 005 number. The thing to remember here is that if you used your middle name (or initial) on the ticket, this is simply appended onto your first name without a space. Make you put in exactly what's on your ticket or it will not recognize it. But try all the combinations/permutations of it anyway. Mine was my first name with my middle initial.
I hope that helps. Unfortunately I can't speak to it asking for an email address because I've never seen that before. It's possibly a new thing. I'd use the address that is on the eticket, but I'm assuming that's the one you used.