Even Muttprint contains bugs. Following problems exists currently:
Problem with parsing of the configuration file (RedHat Linux). Because of a bug in the Perl version distributed with RedHat Linux 9.0, Muttprint cannot parse the configuration file in a UTF-8 environment. You can use Muttprint in a non-UTF-8 environment or upgrade Perl from RawHide. The bug is described at http://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=98274.
Error in line-wrapping with Perl 5.6. Lines that contain non-ASCII characters are wrapped too early in all Perl 5.6.x versions (earlier versions don't work at all). Umlauts and Cyrillic characters count twice. The problem occurs in all locale environments and bases on a bug in the standard module Text::Wrap in this Perl versions. The bug occurs only if the mail contains lines which are too long and you don't see it in a normal German or English text. You can increase the value of WRAPMARGIN (see Section 3.1.14) or use a up to date Perl (recommended is 5.8.1).
Wrong printing of the date (Perl 5.8.0). The date is printed wrong if it's printed in the language of the country (see Section 3.1.7) and if it contains non-ASCII characters. The problem is that the mentioned Perl version encodes the UTF-8 encoded string again in UTF-8. The result is a quasi twice-encoded date. There are improved versions of Perl 5.8.0 where this problem is solved (for example the Perl distributed with Debian unstable).