Looked for, couldn't find, looked for, thought I found, ... hrm, what's this?... nope, it wasn't... looked for, found something else, used it...
erm...
anyway,
I ran "Disk Utility" on my Mac to see if things were working right because I started having trouble installing the newest version of a program. Disk Utility does a verification of my hard drive and found several problems, of which the most serious was
"Invalid volume free block count
(It should be 36413940 instead of 36235151)"
Now to repair one's boot drive on a recent Mac (with operating system "earlier than 10.5"), one needs to get out the boot CD the computer comes with, put it in, restart it with the button C held down... and run Disk Utility again, this time from the copy of Disk Utility that's on the CD, not on your computer, basically. (So that it can repair your your hard drive without having any programs - including itself - on the hard drive running and changing things on it, I think...) ...
Then I found I'd misplaced the boot CD.
Seriously misplaced it.
... search, turn over room, look at underside of room, toss, bake room, toss room, search room again... oie... find "TechTool disk"... run TechTool, do another test... (same result, but at least... no more problems found besides that!)... -
then today (ok, a day or two later than all this started) I find the boot CD stuck to one of my regular CDs in the shelf up near the top left of my CD case... around where I thought I put it.
Figures.
Repaired my drive, checked my external drive ForTheHeckOfIt, removed some damaged files from iTunes, replaced them, all seems fine now for the moment, and that.