I've tested your game, but it apears to move as it should and without jittering. (Though extremely fast)

The movement of sprites has nothing to do with refreshrates. Only with time.
Code:
at game start up, get time
while your game is running 
begin
  calculate elapsed time for current frame 
  save newly retrieved frametime

  Player1.x:= Player1.x * elapsed time
end;
This way it does not make a difference if someone is using 60hz, 85 or 100. Nor does it matter if a user has a 3ghz or a 700mhz processor. His sprite will always move at the same speed.