Created attachment 2125 
patch against 0.5.2

~ $ xarchiver 
*** stack smashing detected ***: xarchiver - terminated
xarchiver: stack smashing attack in function <unknown> - terminated
Report to http://bugs.gentoo.org/
Avbruten (SIGABRT) (core dumped)

A debugging session in gdb shows that the problem lies in xa_set_statusbar_message_for_displayed_rows and xa_row_selected:

gtk_tree_model_get (model,&iter,pos,&size,-1); #line 1496 and 1588
returns a guint64 while size is defined as a unsigned long int

A patch is attached