You're definitely on the right track, but whatever you did to find out how many columns there are was wrong, mysql has a handy clause for figuring out how many columns there are, maybe you should try that.
I have been reading around trying everything, but I still get stuck after I found out the injection. I think maybe my problem is that I dont understand what I am supposed to do with the challange. Is there someone I can PM for help. Thanks in advance!