All current rockbox downloads (which is where the CNET link takes you) are considered beta at best. There has only ever been one release, and that doesn't run on iPods.
If the database build is hanging at the same point each time, it means that Rockbox has encountered some tag in one of your music files that it's currently unable to process. In order to find out which one it is, the best method is to copy all your music OFF your iPod (i.e. delete it from there and just have it in your computer), and then copy them back on a few at a time, and see if the Database builds correctly or not after you've done each chunk of files. In this way you can narrow down which file is causing Rockbox to choke.
For reference, the problem is *usually* embedded album artwork, which is usually quite large, and Rockbox doesn't like finding it actually in the music.