Multiplayer walking

[CENTER]Multiplayer walking.[/CENTER]
Im having some trouble with my walking system on a multi-user app that im building. The problem that i am having is that the player can walk perfectly once but then when they try walk again it stops after what the movespped variable is set to then when the user click againthe player will walk perfectly. Then after a couple of clicks it will stop in random places across the course of where the user is going.

You can see my application here: http://dropic.net/chat/index.html

and the walking code is:

http://pastebin.com/nYMvB0Uh