Very odd segfault

[jay <mocat best com>]

Never seen anything like this before... here are a few snips of code, and
the message I'm getting from gdb.

typedef struct {
	GtkWidget *d_area; /* drawing area */
	GtkWidget *ent;
} Darea;

struct {
	GtkWidget *entry1;
		        2;
	......etc
} mystruct;


calling_func(mystruct.entry1, &vbox);


void calling_func (GtkWidget *entry, GtkWidget **box)
{
	GtkWidget *frame;
	Darea *da_en;
	
	frame = gtk_frame_new("framename");
	entry = gtk_entry_new();
	set_default_ent(entry); /* sets text in entry with
					gtk_entry_set_text */
	da_en->ent = (gpointer)entry; 
	
	gtk_container_add(GTK_CONTAINER(frame), da_en->ent);
	gtk_box_pack_start(GTK_BOX(*box), frame, FALSE, FALSE, 0);/*dies
								   here*/
	.....
	....
	...
	..
	.
}

here's the output i get from gdb...

(gdb) n
	gtk_box_pack_start(GTK_BOX(*box), frame, FALSE, FALSE, 0);
(gdb) n

Program received signal SIGSEGV, Segmentation fault.
gtk_type_check_object_cast (type_object=0x8071a40, cast_type=40469)
	at gtktypeutils.c:637
637		gtktypeutils.c: No such file or directory.
(gdb)

Never seen anything like that before...

Everything worked before I added the "da_en->ent = (gpointer)entry;" line,
but I have no idea how the function that segfaults relates to this line.

Thanks for any help...
j