cant recreate window

["Yucehan Kutlu" <yucehan gmail com>]

Hi
i have an app that uses several windows when i create and close one
window, after that if i want to create this window again, i get error
below

(zebra:4121): GLib-GObject-CRITICAL **: g_object_ref: assertion
`G_IS_OBJECT (object)' failed

(zebra:4121): GLib-GObject-WARNING **: instance with invalid (NULL)
class pointer

(zebra:4121): GLib-GObject-CRITICAL **: g_signal_emit_valist:
assertion `G_TYPE_CHECK_INSTANCE (instance)' failed

(zebra:4121): GLib-GObject-CRITICAL **: g_object_notify: assertion
`G_IS_OBJECT (object)' failed

(zebra:4121): GLib-GObject-CRITICAL **: g_object_unref: assertion
`G_IS_OBJECT (object)' failed

Any idea how to solve this

Thanks