Console error from itunes -- _NXSafeOrderMainBelowKey (1001)

Question

The full error message written to console log is:
iTunes[pid#] _NXSafeOrderMainBelowKey: cannot perform window ordering operation (1001)
I don't know what triggers it so I have not successfully replicated it on demand. There may be some little amount of lag time before the error first writes to the log, anyway I have never had an "aha!" moment after starting some particular task in iTunes and then seeing the console log pop onto my screen.
I am running 10.4.8 with itunes 7.0.1, on a 1.5Ghz G4 powerbook. I have seen this error message in earlier Tiger and iTunes versions, however.
Is it just because I might be playing stuff from a playlist that is not necessarily visible in the source panel any more when I do some other operation in the main window?
Since iTunes has come to seem pretty robust, maybe I am abusing its capabilities without realizing it. I note below a few of my typical moves while using iTunes to see if anyone thinks they are problematical.
I will often select some playlist, click on a track to start it playing, then scroll up to the top of the source panel and click on my library, split the main window into browse mode and start hunting around for stuff I might want to put in some other playlist or add to some iPod that I sync manually. An ipod is not necessarily involved when I get the error.
Sometimes I split a large (often a Smart) playlist in the main window into Browse mode because I want to select some or all tracks of an artist or album into a new or some other existing playlist. I might be playing tracks from a third playlist at the time I do this operation.
I will sometimes re-sort my whole itunes Library (i.e. by date added, or composer, etc.) while playing music from some playlist.
I think once in awhile I may start playing music from a browsed Library instead of a playlist, where I may have selected an album and in the bottom pane re-sorted the tracks by clicking on disk number, track number or double-clicking on the column for rating.
I sometimes discover I have left a track's info window open after pasting lyrics into it or looking at the lyric, meanwhile I think that info-window can end up behind some other app's open windows, say TextEdit or Preview after I re-minimize the iTunes window, which I always have set to float when minimized. This scenario seems like a possible culprit, otoh I believe I have gotten the error without having any track window open.
Well you get the idea. I do so love iTunes for generally standing up to this kind of punishment so well. It has been a long, long time since I had any problems with my Library, although I back it up a lot just in case. Thank you, Apple programmers!
Once the "window ordering operation" error routine starts up, the error message will keep writing to the console with some (but not always consistent) frequency.
Since I am not sure what causes the program to start writing this error message, I don't know what to correct. My unhappy solution is usually to quit iTunes and restart it. That works fine... until the next time I happen to create some situation that triggers the message. Doesn't happen every day or even every week. But it's an old familiar friend that I'm now getting tired of.
Guess the true problem here is that I don't know how to AVOID creating the problem.
1.5GHz G4 PowerBook   Mac OS X (10.4.8)   Mac 512k, PowerBook 170, various ibooks, G4 TiBk

Answer 1

If you have figured this out by now, please post the solution - I am having a similar problem getting the audiobooks into my iTunes. I also used to download everything on a Windows Vista laptop with no problem. This is my first Mac, and I'm hoping there is some way around this error.