You should be able to upgrade directly from 4.6 to 4.6.2. Quick instructions are in the 4.6.2 tarball at
openacs-4.6.2/packages/acs-core-docs/www/release-notes.html. Longer instructions, including backup/restore, are missing from the tarball (probably my cvs screwup) but can be found
here (it's 4.5 to 4.6 but aside from version numbers everything is the same).
