Segmentation Fault on gtk_tree_item_remove_subtree

[E3769835 pfc eupvg upc es]

Hi

I am using the gtk_tree and gtk_tree_item to build a tree hierarchy
of a filesystem that can change in runtime (remove end add
catalog-trees).
My problem concerns when  I am using the gtk_tree_item_remove_subtree
function when  I collapsing my TreeItems, I get segmentation fault in
certain scenarios.

Condition for segmentation fault are this structure of expanded
directories

more direcories
      |
     [-]----Dir 1
      |     |
      |    [-]-----Dir 2
more           |
direct-        [-]-----Dir 3
ories            |     |
                    |   [-] Directories under Dir 3
                  [-]-----Dir 4
                  |     |
                  |   [-] Directories under Dir 4
                  |
           more dirextoies etc

Scenario 1

When I select a directory of Dir3, Dir4  etc or some  Directory under
Dir3, Dir4 etc and then collaps Dir 1  I get segmentation fault

Scenario 2

I have Selected a directory  under Dir 3   and then collaps  Dir 2
same thing happens, I get Segmentation Fault
If I select some directory under Dir 4 everything works fine,
It is alwawys the first directory that gives the segmentation fault
in this scenario.

When I checked with  gdb, it  reported  that the program
crashed in gtktreeitem.c in line 632, the line looks like this

---- if(g_list_last(tree->children)->data!=item)-----

The tree exists, but tree->children points at 0x0

I have checked my code over and over  and I canīt  discover
any logical errors on my behalf, but since I am simple novice in GTK
I would really like some help on this one because I am STUCK.

   Many thanks
     Johan,  Sweden