[NaS]

Yeah almost. Remove the ! and one ) and extend it with a break:

Code:

if(MVehicleO[v] == 0)
{
PutPlayerInVehicle(i, MVehicle[v], 0);
MVehicleO[v] = 1; 
break;
}

Without the break it would put the first player in all vehicles and set them occupied.
Put the code into the Vehicle Loop obviously.

And remember to reset the MVehicleO Array when restarting the event.