Erm, perhaps better "mode +l $calc($nick(#,0) + 1)" and not +k...
Make sure you don't get flooded if too many people join at once. I do recommend that you set a member limit about 10 or 15 above the number of channel users, then let the script check it everytime someone joins the channel, then, if number of users is 15 (for instance) and your user limit is 16, let the script add another 10 or 15 users to the limit...
Not sure if you can understand what I'm writing (funny english, lol) but you can ask more help I guess
