try ' zinf -ui lcd ./path/to/music.mp3' (make sure lcdproc is running first)
If it still fails then you may need to recompile Zinf with lcdproc support (under debian i needed to do that but under gentoo it was already compiled in)
cheers! hope the answer is of use, as its so late
(I found this thread accidentally while searching google on how to get lcdproc buttons to work with zinf)