hey,
i dont think its much the attitude,
but there are updates with each version of mIRC,
and im not the greatest scripter in the world, well i suck lol
but
there are commands that are new to each release,
some of the commands your using in your script
might be new to mIRC 6.03
so in order for it to work for your friends theywould have to upgrade,
the only suggestion that i have,
is maybe script in mIRC6.0 or 5.9 or something
and see if there aer simular commands that wil work around
im not sure if there are or not,
but maybe they will,
and maybe they will work with 6.3

sorry im not much help.