GTK warning

[Jeffrey Barish <jeff_barish earthlink net>]

I hate the warning messages that GTK provides because they rarely help me
find the problem.  What does this one mean?

/myprogram.py:118: Warning: g_object_unref: assertion `object->ref_count >
0' failed
  self['myimage'].set_from_pixbuf(mypb)

What object is producing the warning?  I suppose it must be myimage.  What
am I supposed to do?  If I exit the program and run it again, 9 times out
of 10 I don't get the warning.
-- 
Jeffrey Barish