Here is how I got this to work, might/might not work for you.
First, make sure you have Compress::Zlib installed on your server.
Then, in cgi_buffer.pm, find and remove
use MD5;Add:
do "Digest/MD5.pm";
if (!$Digest::MD5::VERSION) {
require Digest::Perl::MD5;
import Digest::Perl::MD5 'md5_hex';
} else {
import Digest::MD5 'md5_hex';
} # end if
After:
OK, now do that instructions as they say.
Once you've uploaded the modified files, reupload the Modules that came with your 6.7 zip, ensuring files are as up to date as possible.