Drop-Down meny

Hi!
New to this forum from today :thumb:
I did the

Creating Drop-Down Menus
by Syko

But when i try the meny button i get this error message :puzzle:

"Error Symbol=main, layer=button, frame=1:Line 1: Mouse events are permitted only for button instances
on(rollOver) {

Error Symbol=main, layer=invisble, frame=20:Line 1: Mouse events are permitted only for button instances
on(rollOver) {

Total ActionScript Errors: 2 Reported Errors: 2 "

I’m farly new to Flash, so i don’t know that much about actionscript, but i did everything from the tutorial and it still doesn’t work… what am i doing wrong !!!