help me get rid "the maximum number of allowed codes ..." in pokemon diamond

I got this error when I want to enable cheat Box 1 HOENN LEGENDS in pokemon diamond...
"Cannot enable cheat code. The maximum number of allowed codes has been reached.."
I wonder.. why is this happening? I don't have any cheat enabled and I can't turn on only this cheat? I cleared (turned off) all my cheats except this one and it can't be enabled too...there must be some error in this cheat.. can someone help me? I'm currently using EDGE card.. and using the latest cheat database from gbatemptthanks before and sorry for my ridiculous english.. I'm from INA

maybe it becaues it a fake cheat and does not work some times that happens

oh I see... thanks for the info... maybe I'll find another fix for the cheat... but I'm pretty sure it's not a fake cheat.. I got it from gbatempt..
everything works except this cheat...too bad I'm not a code guru... T_T thanks! ^^