Problem with forward

[PD123]

Good day,

I have a problem with the forwarding.
When user forwards message (message contains attachments) to other e-mail address ( there is no difference local or other mail provider ) message got corrupt: no attachments (attachment type doesn't matter, i have tried pdf, txt, .doc .etc), text is corrupted (LT or DE symbols is displayed with =xx= symbols) example f=C3=BCr ; pr=C3=A4sentieren

This problem occurs, when messages are forwarded from MS Outlook 2003 or 2010 version Zimbra version Version 6.0.12_GA_2883.FOSS Mar 5, 2011
Server Debian Etch 411

If any additional info is needed please let me know

Regards,
Paulius D