Damn slide bar!

hi everyone!

I’m trying to follow this tutorial here: http://www.kirupa.com/developer/flash5/menudragger2.htm

The problem is: In that slider only are 4 items. The thing is that i need more. If i just add more, the slider only goes 'till half of the 5th item…

What can i make to put this thing working??? Please, somebody help me!!!..