In the continuing evolution of the PEAR.phar package Greg Breaver has been working up, there's a little bit of a setback noted in this new blog entry over on his site.

After receiving some feedback from others, and doing a bit more testing, I found a few problems with PEAR.phar and PHP_Archive: stream_get_wrappers() is a PHP5-only function, the opendir()/readdir() stuff appears to be broken or buggy in PHP 4, and XML_RPC class was not bundled.

[...] The first two problems are saddening, because it means that PHP 4 users simply can't use PEAR.phar - sorry folks. It looks like the latest and greatest features are limited to those who upgrade. In any case, I have replaced the old PEAR.phar with a new one. Those who had problems should simply re-download this one and see if it fixes it (http://pear.chiaraquartet.net/PEAR.phar).

With PHP 5 becoming more and more prevalent in installs these days, I don't see the PHP 5 only kind of issue being as large of an issue in the future. Unfortunately, right now, there are just too many PHP 4 installs out there...maybe there's a workaround out there somewhere...