no$gba error message

hi when i try to play yoshi's island it gives me this error: sorry, no$gba needs a copy of the original gba bios (in a file named gba.rom or no$gba.com) to execute BIOS sound functions
does anyone know how i can fix this?
i got both no$gba 2.5 and 2.6
thanks in advance
Cash

thx for the answer.