Hm, a new variant:
[New Thread -1274991696 (LWP 27984)]
[Thread -1274991696 (zombie) exited]
[New Thread -1274991696 (LWP 29012)]
close failed: [Errno 9] Bad file descriptor
[Thread -1274991696 (zombie) exited]
/home/user/bin/gdb.amule.sh: line 15: 10261 Speicherzugriffsfehler gdb -command=/home/user/.aMule/gdb_befehle /usr/local/bin/amule
user@host:~$
But: aMule is still running! Maybe because after invoking /home/user/bin/gdb.amule.sh, before the aMule window appeared, I switched on a different xfce desktop page (work space), so aMule window was on one work space window, the xterm with the gdb was on the other?