OSX 10.4.11 not accepting external drive for home folder...

I recently had my PowerMac G4 somehow "forget" all of my standard system preferences like mail setup, safari bookmarks, etc. but what really is causing some problems is that OSX is not accepting my WD Passport for my home folder. I've had it set up to do this before so I know how to do it, but it won't stick. I've even logged in as root user and it still didn't work. The only reason I like having the home folder on my Passport is because my main hard drive doesn't have enough space to hold all my music, photos, etc.

If anyone can give me any advice on what to do, I'd really appreciate it.

Thanks in advance,

Zach H.