I have some ATI cards, mostly over 3 years old. ATI is a good company. The Sept 2001 date looks good for addressing most hardware issues I know of, so don't worry about that, unless they simply have revised it to fix developmental errors.
Do you know if your bios is "Award" , or "MR" or "AMI" or what it's called?
The way it works is this. A company, anyone, writes a BIOS. The basic bios is then adapted specifically for each motherboard. Things like Chipset, sound, etc. add/subtract features. It is possible that your specific MoBo Mfgr decided that shadowing is so obsolete that they simply no longer maintain it in their bios revisions. Almost no one need shadowing anymore. You don't, for sure.
You were able to look at several different pages of bios setup, right?
Typically, they have names like (these are Award BIOS for an ASUS Socket 7 Motherboard, but common to most Award BIOS):
Standard CMOS
BIOS Features Setup
Chipset Features Setup
Power Management Setup
PNP & PCI Setup
Load BIOS Defaults
Load Setup Options
Supervisor Password
User Password
IDE HDD Auto Detection
Save & Exit Setup
Exit Setup Without Saving
The place to expect shadowing is in "BIOS Features Setup".
If you don't see it there, don't worry about it.
Here is the most important thing. If teh error returns, or any error returns, you must get all that good info like you did before, even the gobbledy gook. If it happens once or twice more, that stuff will actually tell the tale... for better or for worse.
At this point, my question is an easy one.
1. Have you moved your case, or re-oriented it relative to exit airflow, or maybe next to an extrenal fan or airconditioning duct.
2. Can you determine the temperature inside your case.
3. Can you determine the temperature of your CPU.
4. Is there a temperature variation in the room where the computer is run (e.g, more than about 5 degrees or so)?
Every chunk of silicon has a limit on op temp, before errors begin to propogate. The exact way this happens, I will not get into. Chips are as unique as humans, though... all have individual weaknesses that cannot be seen at normal temps.
I have run many chips and cpus to and past the brink, and it is possible you had a temperature related failure. Those are elusive, and much more frequent in summer months, especially here in the northwest where most of us have no air conditioning. I have megabytes of logs going back years on my machines, and my CPUs (very well cooled) hit about 39-41 C in the winter, and as much as 51 in the summer. Much past 58 and they get squirrelly when I run special programs that detect the onset of chip errors.
Anyway, my guess at this point is its temp related. Which is good news, as that is controllable.
If you can't monitor your temp, tehn just be sure you have an excellent chip heat sink/cooler.
PS, I use MBM (Motherboard Monitor) to keep track of all my fan speeds, temps, history, and even a lot of motherboard settings.
Look here:
http://forums.civfanatics.com/showthread.php?postid=346698#post346698