garnome 0.27.1 
rpm2cpio perl script breaks if you are using a locale
(LANG, LANGUAGE, etc.) with UTF-8 in the string.  Perl
invokes the <:utf8> layer for all open()s and so the first
read of 96 characters will be a read of some larger number 
of bytes... because a few 2-byte sequences happen to be 
legitimate utf-8 encodings. This means that no header 
will be found and rpm2cpio barfs.

The fix is to set binmode on both input and output streams:

54c54,55
<   open(F, "< $ARGV[0]") or die "Can't read file $ARGV[0]\n";
---
>   open(F, '<', "$ARGV[0]") or die "Can't read file $ARGV[0]\n";
>   binmode(F);
102a104
> binmode(ZCAT);

Note that I checked this only for perl 5.8 and have no idea 
what happens with perl 6.x.