qmail-inject: fatal

Hi,
I'm running a qmail server since a few months now, including bill
shupp's patch (qmail-toaster-patch 0.5), spamassassin 2.55,
qmail-scanner 1.16, vpopmail 5.3.20 and maildrop.
Since 3 days I'm having the following problem:
In the logs qmail-inject shows

@400000003f127c0b14fdf854 starting delivery 237: msg 1097933 to local
kendzorra.de-juergen@kendzorra.de
@400000003f127c0b14fe1b7c status: local 1/10 remote 0/20
@400000003f127c0b2f7519ec delivery 237: deferral:
qmail-inject:_fatal:_unable_to_parse_this_line:/Return-Path:_Received:_from_184.244.108.8
0_([184.244.108.80])_by_rly-xr02.mx.aol.com_with_SMTP;_Jul,_13_2003_1:19:00_AM _-0200/qmail-inject:_fatal:_unable_to_parse_this_line:/Return
-Path:_Received:_from_184.244.108.80_([184.244.108.80])_by_rly-xr02.mx.aol.com_with_SMTP;_Jul,_13_2003_1:19:00_AM _-0200//usr/bin/maildrop:_
Unable_to_create_a_dot-lock./

and the mail is resend a hundred thousand times.
I already found some information on qmail-list archives, that
"something in that mix [SA, qmail & vpopmail] is either mangling an
existing Return-Path header, or adding a broken one."
Is there another possible reason for this behaviour, like the sender is
sending a corrupt header, or do I have to search for that in my setup?
If yes, where should I?
Thanks,
Juergen

If you get the same problem, read
http://marc.theaimsgroup.com/?l=qmai...9260927551&w=2