I play guitar but am by no means an expert.
Have you thought of sending the song into Bill brown or checking his
websight to see if he already has the song on tape or maybe on the web to
see if anyone has the chords posted?
Bill Brown has learning tapes for guitar, piano and banjo and they are done
so that the blind can follow right along without writen notes.
http://www.musicvi.com  I think is his sight.
Other than that, if it is a guitar part you are trying to figure out have
you considered they may be using a capo for part of the tune?

Matt