First of all, please use a bit more imaginative thread titles in the future. Almost every thread could be entitled "Help", y'know.
It would also help if you could provide a bit more information on
- your OS
- your version of No$GBA
- any extra programs you are running (eg. No$Zoomer, No$pmp, ...)
- the game you are playing
No$GBA has problems processing too long and/or too many cheats for one game. If this error emerged after you typed in a cheat, try deleting the No$GBA.cht file.