Sorry, the error lines appear in .xsession-errors file when I close amule. There are also 2 Gtk errors before as well.
(amule:4069): Gtk-CRITICAL **: gtk_container_remove: assertion `GTK_IS_CONTAINER (container)' failed (amule:4069): Gtk-CRITICAL **: gtk_container_remove: assertion `GTK_IS_CONTAINER (container)' failed (amule:4069): GLib-WARNING **: poll(2) failed due to: Invalid argument. //COMMENT: (THIS LINE IS REPEATED ABOUT 5000 TIMES) ...Too much output, ignoring rest...