I found RPM binaries for Perl6 but for Fedora and it seems they are not binary compatible with your RHEL version.

I really think the best way to install Perl6 on your OS is to follow the URL of u65 or check this page http://rakudo.org/about/.

Try to get github sources with yum.

For Fedora users, check this page: http://rpm.pbone.net/index.php3

Peace