I posted this as a comment to the bug but since it's already closed, I don't know if anyone will see it.
I don't think the fix in CVS is the right fix.
Instead of gtk_object_unref(GTK_OBJECT(loader)) (which is deprecated), use g_object_unref(loader) without the cast to GTK_OBJECT.
When I use the code in CVS, I get 2 errors about bad cast from pixbuf to object. When I use g_object_unref(loader) in both places, I don't see any errors.
The end user functionality is the same (both work), but when I use g_object_unref, I don't get errors on the console.