Script works on first compile and never again....

Hi all,

Sorry if this is a common question, but couldn't find a reference to my problem.

I have the following script to simulate a hot tub filling with water after it is rezzed from a 'Water Button'. The rezzing and derezzing works perfectly, however, the movement or filling 'illusion' code only works one time when I save the script in edit mode. It works by bumping it up x number of increments (in this case 10 times).

If I take the object, and place it back on the ground, there is no movement. Similarly, when I inlcude it as part of the water tap, the water rezzes to the set point, but doesn't rise.

Why would it only work when I compile and save the script, and never again?

NB. It's currently 3am and my first script ever, am I missing something very obvious?

MoveUp(integer numMoves)
{
    integer counter = 0;
    vector tempTargetPos;
    
    tempTargetPos = llGetPos() + <0.0, 0.0, 0.1>;
    
    while(counter < numMoves)
    {
        llSetPos(tempTargetPos);
        tempTargetPos = llGetPos() + <0.0, 0.0, 0.1>;
        counter++;
    }
} 

default {
    state_entry() {
    
    MoveUp(10);
    
    //rest of code is just waiting for button to be pressed again to empty the water
    llListen( -906, "Water Button", NULL_KEY, "" );
    }
    
    listen(integer channel, string name, key id, string message) {
        if (message == "derez") {
            llDie();
        }
    }
}