I'm pretty sure 4.x ports and binary package support is a tad KIA by now ^_^.
If I had to *try* to update such a system manually, I would probably try either of the following methods to upgrade incrementally by major release until I found one that worked or was forced to reinstall before reaching my target:
fetch csup source code and compile it manually (preferably installing it into a private location: note csup has been in the base since like 6.2R or 6.1R).
Fetch system source code
manually via
Anonymous CVS
if rsync is installed, try fetching FreeBSD from an rsync mirror (I think it's possible, not hat I've ever tried it)
once system is up to date (e.g. 7-Stable or whatever rocks your boat). And assuming the level of mergemastering hasn't kille dyou yet, note down what services are installed packages, save a copy of what you have, delete all, install all.
Code:
vi /root/services.notes
pkg_info > /root/pkg_info.old
# back up your apache, php, and mysql setup first
pkg_delete -fx *
... install software as needed via ports/packages ...
For doing a reinstall, you can just dump every thing important (like your webroot and mysqldumping mysql). Install the new FreeBSD using a total reformat, then setup & restore files as needed and get the services reinstalled.
*just my two cents: I am not employed as a system administrator, follow any advice at own risk*