Homebrew PCBs

Hi, as a newbie i'm trying to learn the methods you are talking about.
Yeterday i tried toner transfer method in the univ's lab, by using HP 
1100 LaserJet, suppiled with it's original HP toner. I printed the
pcb 
design on a piece of green glossy paper that i got from one of the
old 
magazines. Then i ironed the print out to the copper side, for more 
than 10 minuteds, but nothing happened... :((

What could be wrong?

thanks,
utku ates