Follow sprite when the mouse is down, but randomly move when mouse is up?

Question

I have a sprite that has a Random Movement behavior.
While the mouse is down, I want it to stop this behavior and initialize a Follow Sprite behavior instead.
When the mouse is lifted, I want to stop the Follow Sprite behavior and reset/restart the Random Movement behavior.
Openspark helped me out with a different version of a very similar behavior a long while back, which worked. It switched between Random Movement and Draggable. I tried to edit the code so that it would apply to Follow Sprite instead of Draggable, but it isn't working the way I thought it would.
The order of behaviors on my sprite is as such:
followSprite (Follow Sprite)
moveToward (The behavior described above)
randomMove (Random Movement)
turnTowardsMouse (sprite faces mouse when it is clicked)
Face Destination (if not facing mouse, sprite faces toward the randomized endpoints generated by randomMove)
This is the moveToward behavior - the middleman that's supposed to be swapping between the two:
property pSprite
property pTouching
on beginSprite(me)
  pSprite = sprite(me.spriteNum)
end beginSprite
on mouseDown(me)
  -- Overrule the Random Movement and Rotation behavior until the mouse
  -- is released. See the on prepareFrame() handler for the effect.
  pTouching = TRUE
end mouseDown
on prepareFrame(me)
  if pTouching then
    -- Block the event from reaching the Random Movement and Rotation
    -- behavior, so that only the Draggable behavior will work.
    if the mouseDown then
      stopEvent
    else
      -- The user has released the mouse.
      -- Start a new movement in the Random Movement and Rotation behavior.
      pSprite.pPath = VOID
      sendSprite(pSprite, #mNewPath)
      pSprite.pRotate = VOID
      sendSprite(pSprite, #mNewRotation)
      pTouching = 0
    end if
  end if
end prepareFrame
Can anyone help me figure this out?
If you want to imagine a visual, it's essentially a touchscreen fish tank. Fish swim around randomly, but when someone is touching the screen, they approach the point of contact (which is defined by a tiny invisible sprite centered on the cursor).
Once again, thank you so much to anyone who can help me out. This is part of a capstone undergraduate art project I am doing - and I am far more experienced in making the visuals than I am in coding. I am having to mostly tackle Lingo on my own. Any coding help I've received will be recognized (with permission) on my artist website as well as a thesis paper I am writing that will be published in May.

Answer 1

As first steps at troubleshooting you could try an SMC reset and a PRAM reset:
SMC Reset
Shut down the computer.
Unplug the computer’s power cord and disconnect peripherals.
Press and hold the power button for 5 seconds.
Release the power button.
Attach the computers power cable.
Press the power button to turn on the computer.
Reset PRAM
Shut down the computer.
Locate the following keys on the keyboard: Command, Option, P and R.
You will need to hold these keys down simultaneously in step 4.
Turn on the computer.
Press and hold the Command-Option-P-R keys. You must press this key combination before the gray screen appears.
Hold the keys down until the computer restarts and you hear the startup sound for the second time.
Release the keys.
If that doesn't help, what OS are you running? Depending on the OS (Lion/Snow Leopard) will help determine the next step.