problem deleting special chars

["Hartwig, Thomas" <t.hartwig@xxxxxxxxxxx>]

Hello,

since my installation of zsh 4.1.1, I have problems deleting special 
chars in the shell. I use german layout keyboard and deleting of umlauts 
like "ä", "ü" does not work any more. If I want to delete such a char I 
have to press the backspace key twice and the position of the cursor is 
broken. I used zsh version below 4.0 before, so I can't tell exactly at 
which version this happend. This is independent from the settings of the 
 shell, I tested this without a zshrc as well.

Thanks for any suggestions
Thomas

environment:
$ echo $TERM
xterm
$ echo $LANG
en_US.UTF-8 (other language settings tested as well)
$ cat /proc/version
Linux version 2.4.22-ac4 (root@nautilus) (gcc version 3.2.2 20030222 
(Red Hat Linux 3.2.2-5))
begin:vcard
fn:Thomas Hartwig
n:Hartwig;Thomas
adr:;;Boppstr. 11;Berlin;D;10967;Germany
email;internet:t.hartwig@xxxxxxxxxxx
tel;work:+49 30 69599727
tel;fax:+49 30 695969444
tel;cell:+49 172 3265984
note:GnuPG/PGP: 0xC51B523B
x-mozilla-html:FALSE
url:http://www.crapoud.com
version:2.1
end:vcard