[Sew_Sumi]

SetPlayerTeam stops players taking damage from teammates. You need to track their team through their enum or an array, and avoid using it.

Quote:

Originally Posted by wiki * Players can not damage/kill players on the same team unless they use a knife to slit their throat. As of SA-MP 0.3x, players are also unable to damage vehicles driven by a player from the same team. This can be enabled with EnableVehicleFriendlyFire. * 255 (or NO_TEAM) is the default team to be able to shoot other players, not 0.

Just so it's clear, the tutorial doesn't even say to use SetPlayerTeam for this very reason, yet your script is using it, and that is causing the problem.