[Shinja]

return in a loop breaks it, do it like that
forward RespawnAllCars();

PHP код:

public RespawnAllCars() 
{ 
    for(new i=0; i<cache_get_row_count(); i++) 
        { 
        new vid = cache_get_field_content_int(i, "id"); 
        if(!IsVehicleOccupied(vid)) && (strcmp(Vehicle[vid][vOwner], "Nobody")) ReloadVehicle(vid); 
         } 
    SendClientMessageToAll(-1,"{FFC300}Unoccupied vehicles have been respawned."); 
    return 1; 
} 


And i don't think you really need a query for it, use GetVehiclePoolSize better

PHP код:

public RespawnAllCars() 
{ 
    for(new i=0, j=GetVehiclePoolSize; i<j; i++) 
        { 
        if(!IsVehicleOccupied(i)) && (strcmp(Vehicle[i][vOwner], "Nobody")) ReloadVehicle(i); 
         } 
    SendClientMessageToAll(-1,"{FFC300}Unoccupied vehicles have been respawned."); 
    return 1; 
}