Help with basic script

I have just started scripting and I'm struggling trying to get things to work. I've read a lot but still can't figure it out. A little help would be greatly appreciated. 

Basically, there are two things not working on my script, the delay im trying to put (using sleep function) just doesn't work. Also, the hotkey to stop the script doesn't work either.. So everytime I try and test it, I get stuck with my mouse clicking everywhere... 

everything else seems to work out fine but if you guys have any ideas... I'm ready to try anything. Just a little hint could be really great!

Thanks in advance. 

HotKeySet("{ESC}", "Exit")

WinActivate ("Windowname")

Local $t =  Number(0)
Local $x
$x = Number(703)

While $t < $x
$coord = PixelSearch(0, 155 ,1919, 1020, 0x4c950c, 12)
  if Not @error Then
         MouseMove ( $coord[0], $coord[1], 4 ) 
         Sleep(1507-1794)
         MouseClick("left")
         Sleep(24207-42593)
         $t += 1
  EndIf
WEnd