cant upload mp3 files

Hi, my name is carlos, and i have troble when i try upload mp3 files in ninjaxplore. what i can do to solved my problem? i change php.ini maxfiles upload 100m, and in joomla i put in administrator mp3 file to upload manager, but i still can"t upload mp3 files. sorry my english im BRASILIAM GUY.TKS