Pear Package Manager Install Fails on Mandrake 9.0

I'm running a Mandrake 9.0 installation. When I attempt to install the package manager, it fails with the message: 'xml' PHP extension is not installed Presumably this is some xml extension other than either the XML Parser that the package manager itself it attempting to install at the time or the "built in" xml extension referred to in the XML Parser documentation. The message and symptoms appear to be identical to the error message reported on this list by Jeffery Cann last August, but I can find no reply to his message other than Tomas VV Cox's unhelpful taunt to "read the error message". To which specific xml extension does this error message refer? (There are 11 in Pear alone!) Where does one find this particular xml extension? How does one go about adding it to a PHP 4.2.3 production installation (i.e. recompiling is not an option) running on Mandrake 9.0? ...and more generally, is there a compendium of Pear error messages that expand upon the rather terse verbiage the occurs at the time of each individual catastrophe. -- RAM PS - subscribing to the digest version of this lists appears to provide a broken "send to the list" link at the top of the welcome page.