Rollover button script

Hi all,
I’ve tried to make rollover buttons, following a bunch of tutorials. I’m a noob, but I’m sure I’ve done everything correctly!
Basically, the compiler shouts at me, while, another .fla that I downloaded and tried to follow with tutorial works perfectly.
I’m a little frustrated… Please could a kind person show me the way?
Thanks for considering…

BTW: I’ll attach the file that I’m trying to recreate…