WISH Music Time requires Tcl and Tk 8.5 or greater. For best results, download and install ActiveTcl 8.6.4 Community Edition (http://www.activestate.com/activetcl/downloads), then add your ActiveTcl /bin directory to your PATH and also s-link the "tclsh" and "wish" executables to /usr/bin. (You can also just install Tcl and Tk 8.6.0 or so from the Ubuntu repo.)
It also requires an audio player to play .mp3, .wav, and .ogg files. To play MIDI files, it requires TiMidity. If you have mp3blaster installed, WISH Music Time will use it by preference to play audio files. If not, it will use your default audio player if it's designated by a link or script called /usr/local/bin/defaultaudioplayer. Otherwise, you can use the Options button to choose your own installed audio player from its location in the directory structure. If you have ffmpeg installed, WISH Music Time will use it to find out the playing time of the files to be played by your audio player, without actually playing them first. If you don't have ffmpeg, it will note the playing time after playing a file for the first time.
I've squashed all the bugs I could find, but please let me know if you find any that I didn't, and I'll try to squash them too.