Problem L1 M7 for custom mission

it's taken several error when i start mission from L1 M7 check this out !

SelectMission("m7");

SetMissionResetPlayerInCar("m7_carstart");
SetDynaLoadData("l1z6.p3d;l1r6.p3d;");

UsePedGroup(7);

AddStage(0);
SetStageMessageIndex(24);
AddObjective("getin");
SetObjTargetVehicle("current");
AddStageVehicle("smith_v","m7_smithers_carstart","race","Missions\level01\M7race.con", "smithers");
CloseObjective();
CloseStage();

AddStage(0);
RESET_TO_HERE();
SetMaxTraffic(2);
SetStageMessageIndex(25);
SetHUDIcon( "mansion" );
AddStageVehicle("smith_v","m7_smithers_carstart","race","Missions\level01\M7race.con", "smithers");
SetVehicleAIParams( "smith_v", 0, 1 ); // very dumb - no shortcuts
SetStageAIRaceCatchupParams("smith_v", 80, 0.5, 1.1, 1.7);
SetStageAIRaceCatchupParams("smith_v", 80, 0.5, 1.5, 1.7);

SetStageAIRaceCatchupParams("smith_v", 80, 0.5, 1.5, 1.7);

AddStageVehicle("cPolice","m7_villain_carstart","NULL", "Missions\level01\M7Chase.con");

AddStageVehicle("cPolice","m7_villain2_carstart","NULL", "Missions\level01\M7Chase2.con");

AddStageVehicle("cPolice","m7_villain3_carstart","NULL", "Missions\level01\M7Chase3.con");

StartCountdown(count);
AddToCountdownSequence( "1", 1000 ); // duration time in milliseconds
AddToCountdownSequence( "3", 1000 ); // duration time in milliseconds
AddToCountdownSequence( "7", 1000 ); // duration time in milliseconds
AddToCountdownSequence( "15", 400 ); // duration time in milliseconds

AddStageWaypoint( "m7_AI_path4" );
AddStageWaypoint( "m7_AI_path9" );
AddStageWaypoint( "m7_AI_path13" );
AddStageWaypoint( "m7_AI_path13" );
AddObjective( "race", "both" );
AddCollectible("m7_AI_path13", "carsphere");
// SetCollectibleEffect("finish_line_col");
CloseObjective();
AddCondition("position");
SetConditionPosition(1);
CloseCondition();
AddCondition( "damage" );
SetCondMinHealth( 0.0 );
SetCondTargetVehicle( "current" );
CloseCondition();
AddCondition("outofvehicle");
SetCondTime( 10000 );
CloseCondition();
CloseStage();
AddStage(1, "final");
SetStageMessageIndex(26);
SetHUDIcon( "burns" );
AddStageWaypoint( "m7_burns_path1" );
AddStageWaypoint( "m7_burns_path2" );
AddObjective("destroy");
ActivateVehicle("burns_v","NULL","target");
SetVehicleAIParams( "burns_v", -10, -9 ); // no shortcuts
SetObjTargetVehicle("burns_v");
AddStageVehicle("cPolice","m7_villain_carstart","NULL", "Missions\level01\M7Chase.con");
ActivateVehicle( "cPolice","NULL","chase" );
AddStageVehicle("cPolice","m7_villain2_carstart","NULL", "Missions\level01\M7Chase2.con");
ActivateVehicle( "cPolice","NULL","chase" );
AddStageVehicle("cPolice","m7_villain3_carstart","NULL", "Missions\level01\M7Chase3.con");
ActivateVehicle( "cPolice","NULL","chase" );
CloseObjective();
SetStageTime(300);
AddCondition("timeout");
//SetHitNRun();
CloseCondition();
CloseStage();

CloseMission();

//dialogue_hands_in_air
//dialogue_hands_on_hips
//dialogue_scratch_head
//dialogue_shaking_fist
//dialogue_thinking
//dialogue_yes
//dialogue_no
//dialogue_cross_arms
//dialogue_open_arm_hand_gesture
//dialogue_shake_hand_in_air

i try to change a several basic and it's always dosen't work i'm tired of many error this is strange !
so guys can you help me for better basic to be working on L1 M7 possible plz !

Well, from what I understand, first of all, you did not add a stage vehicle "burns_v", only activated it.
So, you might aswell want to add this line under the rest of "AddStageVehicle"
AddStageVehicle("burns_v","{locator}","race","burns_v.con", "burns");
Where {locator} is any locator of your choice.

Also, did you load any "cPolice" or "burns_v" in the m7l? It's not going to work unless you tell the game to load them in there, should be something like:

LoadDisposableCar("art\cars\burns_v.p3d","burns_v","AI");
LoadDisposableCar("art\cars\cPolice.p3d","cPolice","AI");

I hope this helps!
If there is any other error I did not point out myself, I'm sorry, I hope someone will.