First, make sure that the folder you want to add contain .mp2, .mp3, .aac, .au, .ogg, .ape, .flac, .aiff, .m4a, .mpc, .ac3, .wav, .wma1, or .wma2 files. After that open the software, click the Add Folder button, select the folder you want to add and press OK instead of double-clicking its icon. If it doesn't work, remove the program using its uninstaller or Add or Remove Programs feature and download and install the latest version of the software.