Mailscanner with Mailwatch / RPC Problem

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Hi you,

sorry for mistakes, i´m new ot this list here ;)
I try for at leat three days to get mailscanner and mailwatch working 
with XML RPC,
but, everything i do, i geht this strange error in the webinterface:

---GOT---
HTTP/1.1 200 OK
Date: Mon, 17 Nov 2008 10:58:10 GMT
Server: Apache/2.2.9 (Debian) PHP/5.2.6-5 with Suhosin-Patch mod_ssl/2.2.9 OpenSSL/0.9.8g
X-Powered-By: PHP/5.2.6-5
Content-Length: 176
Connection: close
Content-Type: text/html; charset=UTF-8

<br />
<b>Catchable fatal error</b>:  Object of class xmlrpcval could not be converted to string in <b>/var/www/mailscanner/xmlrpc_1.2/xmlrpcs.inc</b> on line <b>425</b><br />

---END---

HEADER: Date: Mon, 17 Nov 2008 10:58:10 GMT
HEADER: Server: Apache/2.2.9 (Debian) PHP/5.2.6-5 with Suhosin-Patch mod_ssl/2.2.9 OpenSSL/0.9.8g
HEADER: X-Powered-By: PHP/5.2.6-5
HEADER: Content-Length: 176
HEADER: Connection: close
HEADER: Content-Type: text/html; charset=UTF-8

XML error: Invalid document end at line 2
XML-RPC Error: Invalid return payload: enable debugging to examine 
incoming payload (XML error: Invalid document end at line 2)

Is there someone out there having this setup (Debian Lenny, Mailscanner 
& Mailwatch newest version & XML RPC) running?

Thanks,
Bastian