problem with gtk filetree

[Glitch <brandon ovnet com>]

hello,

I got Developing Linux Applications Using GTK+ (written by Eric Harlow).

In it there is an example of a Gtk Tree and Gtk List.  It basically uses 
the directories and files in the CWD and displays the contents in a tree 
with leafs.

I can get the application to compile just fine however when I try 
selecting a directory or file I get a seg fault. I can hit the + or - 
sign to expand or collapse a branch but selecting anything but the top 
node causes a seg fault. Here is the actual message:

Gtk-WARNING **: invalid cast from `(unknown)' to `GtkList'
Segmentation fault


Now, normally I'd post the source code but since it's 178 lines long I 
won't put anyone thru that torture (although this may be impossible to 
get help on w/o someone looking at the source, maybe someone has the 
book?).  I understand teh actual error message however since it's not a 
compiler warning/error, in which i'd be given a line number for the 
invalid cast, I have no idea what to change.  I have attempted to make 
some cast changes but then I actually do get compiler errors.

Is there anything I can do to get this working? Post source code? Maybe 
try to learn gdb to find out where it's hiccuping? Anything?

I'd like to get this working as I'll be one step closer to making a GUI 
frontend to my Rio mp3 player.

thanks