Check the mta.xml file, i think you did not set the gamemode as race.
If this is not the solution of your problem try to convert your map to another version of MTA map. You my use this: http://convertffs.com/
the base is a map but the car spawners and the moving gates are .lua script. Take a look in the community, you'll probably find what you are looking for, then you have to make a script using the function createObject and moveObject in order to create the gate and move it while approched.