GtktreeView & Model segmentation fault

[Van H Tran <tvhoang1980 yahoo com>]

Hi all,

I get a "Segmentation fault" in a gtktreeview i'm
using. Basically, it's a Treeview with expandable
folders (like a file browser) 

The problem is: The program crashes very randomly when
i just try to click to expand/collapse the folders,
particularly when the tree has depth >= 3. After a
certain number of clicks (sometimes 10, sometimes
more), i get a segmentation fault. Inserting debugging
messages doesn't help either as it also crashes at
some random instruction...
 So i'm just clueless and can't track what exactly
went wrong here. The randomness really buggers me.

Does anyone have any advice on this? Is there some
error with my GtkModel or memory allocation, possibly?
Some common error with GtkTreeView that i am missing?
Or what tools can i use track this problem down? 
The code is rather messy so i don't want to post it
here.

Thanks a lot for any advice.
Cheers,
TranVan Hoang