I had to update to the latest vBulletin 4, but for that I needed php5.3. Luckily, RHEL has put out php53-* packages (I installed php 5.3.3-1.el5_6.1 btw). I downloaded them all but they were missing php53-pear* package. I’m not sure if this is just the case for x86_64.

So the main problem was getting PEAR packages to install. I tried to get the newer way of downloading pear packages, pyrus (pear2). However, the command php pyrus.phar install ___ resulted in messages like these:
The sqlite3 extension is required.
You must compile PHP with sqlite3 enabled, or install the necessary extension for your distribution.
(Not sure which extension of php53 would resolve this)

The sqlite3 extension is required.
You must compile PHP with sqlite3 enabled, or install the necessary extension for your distribution.
(This one is resolved by downloading php53-xml, thankfully available)

Anyhow, I didn’t want to go on a hunt to try to get these php53 special packages by following the instructions listed in the manual. However, the url listed in the manual http://pear.php.net/go-pear.phar makes php-fcgi put up a blank/empty page. I had a feeling it’s these .phar (weird php compressed archives) files that they’re using. Luckily in the comments, I noticed somebody said to get http://pear.php.net/go-pear. Now that my friends worked like a charm. All I had to do was download that to the server, open it up in the browser and follow the steps as it shows.

The rest comes easy. If you got questions, fire away.