Pierre-Alain Joye has posted this new note today about the release of PEAR 1.4.10.

I just released PEAR-1.4.10 (Greg released it again later, I forgot to commit the new state, stable ;) ). Besides many bug fixes, this release boost the open_basedir and safemode support.

Also, I really hope it is the last 1.4.x release, we will now focus on PEAR 1.5.x and up but more about that later this week.

With this new update, you can finally run the installer with open_basedir in effect, as corrected with two new config options. You can grab the latest update here.