These are new files. I don't recall seeing the mppe folder there a few days ago when the update4 was first released.
For the benefit of others here is the section from the readme file at
ftp://ftp.e-smith.org/pub/e-smith/updates/5.6/Update4/RPMS/mppe/READMEPPTP ppp-mppe kernel modules
----------------------------
The mppe sub-directory contains the mppe kernel modules for all kernel
architectures. The correct module is required to enable the PPTP server
to function.
The SME Server 5.6 CD only contains the i686 kernel variant.
To install the athlon specific kernel module, download
it and then run:
rpm -Uvh --replacepkgs ppp-mppe-modules-2.4.2-4es.athlon.rpm
/sbin/e-smith/signal-event post-upgrade
/sbin/e-smith/signal-event reboot
Regards
Ray Mitchell