I'm wondering why, under the BEFORE YOU INSTALL heading, it tells you to move xoops_lib and xoops_data out of the root directory? As counterintuitive as it sounded (why install directories only to move them before install??), I did just that and had to move them back again. Had I not been more experienced in installing PHP/mySQL applications on my website I would have been hopelessly stymied. You should make this clearer to users who don't know their way around a website as well.

It was before in the post installation instructions.
The advantage was that the installation was less complicated.
(Some servers have no provisions for outside root PHP execution.)
The disavantage was that it stayed many times inside the root, with a lot of hacked sites as a result. Because once a site seems to be working, people didn't care about instructions.
Therefore it was moved to the pre installation instructions to ensure that people observe the placement.

Thanks for your reply, ghia. I guess it's just a problem with syntax and phrasing - now that I'm gradually getting the hang of how things work it makes more sense.