[Users] Problem with xmpp module

Hello, I try to set up an IM gateway between a Jabber server (namely jabberd2) and OpenSER. I have not been a really original person as I have just followed the small tutorial given by Daniel-Constantin Mierla at FOSDEM 2007. But I have a small issue here. I have no problem sending messages from a jabber client to a SIP client but sometimes I can't send a message from my SIP client to the jabber client. I get the following trace : Apr 18 13:02:01 devlnx /usr/local/sbin/openser[12925]: message to XMPP : from <sip:8374@mydomain.test> to <sip:antoine* xmpp.mydomain.test(a)sip-xmpp.mydomain.test&gt; Apr 18 13:02:01 devlnx /usr/local/sbin/openser[12925]: xmpp: invalid content-type 0x300ff Apr 18 13:02:02 devlnx /usr/local/sbin/openser[12930]: message to XMPP : from <sip:8374@mydomain.test> to <sip:antoine* xmpp.mydomain.test(a)sip-xmpp.mydomain.test&gt; Apr 18 13:02:02 devlnx /usr/local/sbin/openser[12930]: xmpp: unable to write to command pipe: Bad file descriptor Apr 18 12:04:01 devlnx /usr/local/sbin/openser[12440]: WARNING: script writer didn't release transaction When i send a message successfully I get : Apr 18 12:47:32 devlnx /usr/local/sbin/openser[12718]: message to XMPP : from <sip:8374@mydomain.test> to <sip:antoine* xmpp.mydomain.test(a)sip-xmpp.mydomain.test&gt; Apr 18 12:47:32 devlnx /usr/local/sbin/openser[12718]: xmpp: invalid content-type 0x300ff Apr 18 12:47:33 devlnx /usr/local/sbin/openser[12715]: message to XMPP : from <sip:8374@mydomain.test> to <sip:antoine* xmpp.mydomain.test(a)sip-xmpp.mydomain.test&gt; My configuration file is the classic, out of the box openser.cfg for a proxy with the configuration described in the FOSDEM presentation included before the uri checking. Do you have an idea of what the problem can be, and how I can solve this ? Thank you in advance for your answers, Antoine