how have I managed to break gtk_button_new_with_lable?!

[rob <mailingLists pangolin org uk>]

Here's my bit of code

static void
AttrEditingFrame_init (AttrEditingFrame *self)
{
        GtkWidget *vbox;
        GtkWidget *newAttrButton;
         
        self->attrEntries = g_ptr_array_new();
        
        vbox = gtk_vbox_new(FALSE, 5);
        
        newAttrButton = gtk_button_new_with_label ("New Attribute");
        gtk_signal_connect (GTK_OBJECT (newAttrButton),
                                        "clicked",
                                        create_attr_cb,
                                        self);
        gtk_box_pack_start (GTK_BOX (vbox),
                            newAttrButton, 
                            TRUE, TRUE, 5);

        gtk_container_add (GTK_CONTAINER (self), vbox);
}

It segfaults every time when it gets to gtk_button_new_with_label

Under the terminal it says:
Gtk-CRITICAL **: file gtkstyle.c: line 611 (gtk_style_ref): assertion
`style->ref_count > 0' failed.

Under gdb it says:
Program received signal SIGSEGV, Segmentation fault.
0x4059934d in free () from /lib/libc.so.6

any one have any idea I'm completly stumped 

rob