My OS was centos 5.8 and was trying to install Phing for PHP Application packaging. However, installation would fail because of the old PEAR that I had. The pear that I had was from yum installation.
It turned out that I had to manually upgrade to the latest pear and the instruction that I found was at:
http://pear.php.net/manual/en/installation.getting.php
If old pear from the installation via YUM is on the OS, even updating PEAR itself would fail. Only way to upgrade is to do it manually per the instruction.
wget http://pear.php.net/go-pear.phar
php go-pear.phar
The one that I used for the base dir during the installation was :
/usr/share/pear instead of /home/${USER}/pear.