[otrs] Problem with encoding

Hello all! I have installed otrs 2.4.7 and I have problem with sending e-mail: in e-mail (only headers are affected) some non-English letters transform into "??" but other is normal. My environment: FreeBSD 7.3 (KOI8-R), Perl 5.10. For example, one of my Subject (as is): "Subject: [Ticket#016]=?UTF-8?Q?=20=D0=BD=D0=B5=20=D0=BF=D0=B5=D1=87=D0=B0=D1=82=D0=B0?= =?UTF-8?Q?=D0=B5=D1=82=20=D0=BF=D1=80=D0=B8=D0=BD=D1=82=D0=B5=D1?= =?UTF-8?Q?=80?=" What should I do to repair this problem? Thanks.