Collision Sensor not Working! did all fine! FAST!!

helo, I REALY NEED HELP! i have grand contest in 4 Days and realy need help with blender

-i am making flying game

as u can see here! and i want to make Collision sensor to when i touch simple coin, coin dissapears, my plane is no colision and coin sensor!
-but it doesnt works, i add property to plane and all like in one tutorial, but collision, near, and radar Sensors Doesnt work! i even changed plane to dynamic static…etc, but dont know reason!
Please help!

If your plane is set to No Collision, it won’t detect any collisions. If you have a separate object for detecting collisions with coins (and if it’s set to Sensor collision mode), ensure that it’s placed correctly with Physics Visualization (in the Game menu). Also, ensure that the coins aren’t set to “No Collision”, or “Sensor” mode. Sensor mode is for detecting collisions, not causing them.

If you need more specific help, post a blend file. By the way, your game’s looking pretty cool.

make sure the plane is set to “actor” on the physics tab