Try this:

on 1:JOIN:#: {
if ($nick == $me) {
var %a 1
while ($readini(channels.ini,Chan-List,%a) != $null) && ($readini(channels.ini,Chan-List,%a) != #) {
inc %a 1
}
writeini channels.ini Chan-List %a #
}
}
alias joinmychans {
var %a 1
while ($readini(channels.ini,Chan-List,%a) != $null) {
join $readini(channels.ini,Chan-List,%a)
inc %a 1
}
}

The blue monkey is out of its barrel...