on *:TEXT:!balance:* { msg $chan /w $nick To view your bank balance type in your pin (a 4 digit number) }

this doesnt work, how can i make it work?
i want it to whisper the user that sends !balance

Whispers is on the Group chat servers so you need to be connected to that for it to work. You can use this script http://hawkee.com/snippet/16488/ (the mTwitch.GroupChat.mrc one but read the Requirements) and then use /msg $nick to whisper someone.

PS: Twitch is updating the Whispers soon and might not support whispers via IRC after that.