[glade--]question about using the list or tree view

I have just started using glade and am having trouble using the list or tree view feature for glade. I'm simply trying to figure out how it works and all i do is add a new window and add a tree view to it. I then build the project and make it. I then try to add coding from a previous project that has a tree view in it yet i always get a segmentation fault even though they appear to be identical coding... Below i listed the only code i added to the files which were window1.cc, window1.hh, and 1 line to window_glade.hh. I am wondering if I need to modify some other code because I added a line to the window1_glade.hh. I've tried making several programs and messed with some things in the window1_glade.hh, window1.cc, and window1.hh. I've tried not having any changes to the _glade.hh and still get the segmentation fault. Does anyone know what exactly a segmentation fault means? Also is there anyway for me to detect what's causing it? I've found that the lines where i add the columns in the window1.cc file as well as the line where i set the model cause the segmentation fault. Any help will be extremely appreciated as I am at a standstill till I can figure this out