Twilight Menu ++ Cheats

I'm trying to use cheats for my pokemon white ROM on twilight menu, i downloaded a usrcheat.dat and the cheats are showing up in TM++ but even when I apply them and try to use them in game they dont function. For example I tried to use a Rare Candy cheat and I applied it and the instructions said to press select in game to receive them, but when I do so nothing happens. Am I missing something?