Code:
public OnPlayerUpdate(playerid)
{
//DRAG
new ID;
if(Drag[ID] != -1)
This is a problem.
You likely meant to be using playerid, as ID is a fresh variable, and has no value, so the array will always reference ID, which will probably be 0.
Considering that within 4 lines I've already noticed a real issue with your code, it should be a given you're going to have to review your code and actually understand script.