Is flash to flash comunication via fscommand() unreliable?

I am an intermediate flash user.

I downloaded a source file from macromedia that uses fscommand()
to send vars between movies. It didn’t work.

I downloaded another source file from another site - nada! it didn’t work either.

Is it cause I use a mac OSX? (I tested on Safari, IE, Firefox and Opera)

Right now I am wondering if its a method worth trusting.

Please enlighten me