Infinite Menu help

I have recently found the infinite menu tutorial and it dosnt work. When I go to the left it chops back to the begening. I added the secont movie clip butit still chops, the stage is 700 by 700 if anyone see somthing wrong please help me.

onClipEvent (load)
onClipEvent (enterFrame)
   var distance=_root._xmouse-xcenter;
   if (_x > 0) _x=-700;
   if (_x < -700) _x=0;