Invalid key length on hard drive. Can this be fixed?

Question

Hello,
I have a question about an error I am receiving with a hard drive I have been using for a few months on an imac G3 (the slot loading version). I bought this used 80 GIG hard drive on ebay for a friend of mine and I helped him transfer all his data from his older 9 GIG drive to this newer 80 GIG drive that I bought for him on ebay. I simply cloned the 9 GIG drive onto the new drive using Carbon Copy Cloner. There is not a lot of data on the drive - only about 3 GIGs of data.
The drive is the only drive in the computer (an imac G3) and therefore it is the startup drive. The operating system on the drive is OS9. All was working fine for a few months until just last week. Now I am receiving this following error:
error message:
The disk "Macintosh HD" appears to be damaged. Use a disk repair utility to repair the disk.
And so I used the disk utility built into OS9 to see if I could repair the problem. (I think OS9's disk utility is called "Disk First Aid")
When using OS9s disk utility (I think it is called "Disk First Aid") the following report is issued:
Problem: Invalid key length, 4,943
Test done. Problems were found but Disk First Aid cannot repair them.
My questions are:
What is an "Invalid key length"?
How serious is this?
What would cause this?
Could this have been caused by the physical condition of the disk or possibly by the software on the disk?
Would re-formatting the drive fix it? (Of course I would try to save any data first onto another disk)
Or is it risky to continue to use this disk even after reformatting it?
I guess I have a lot of questions here and if anyone could make any suggestions or comment on why "Invalid key length" errors happen I would really appreciate it. Thanks:)
Here are some details:
When I bought the 80 GIG hard drive from ebay the first steps I took were to format the drive using OS9's "drive setup", load the OS9 drivers and then I verifed the disk. The disk seemed to be fine. Then I cloned his old drive onto this 80 GIG drive using Corbon Copy Cloner. I was sure the 80 GIG drive was in a healthy state at that time and I trusted it enough to give it to my friend for his startup drive. Now that the drive has failed with his data and programs, I feel pretty bad. How could this "Invalid key length" error occur?
Should I go back to the person who sold me the drive on ebay and ask for a refund? Or are "Invalid key length" errors a common occurance with hard drives that should just be accepted? Or might it possibly be the contents (data) on my friend's disk that caused this error.
It has been suggested to me to use "Tech Tools Pro" or "Disk Warrior" to repair the disk. Hopefully that might repair the disk. Unfortunately these programs are too expensive for this purpose because they would cost more than the computer actually costs (its an old imac G3 computer). I found a service that would run Disk Warrior on the disk to repair it for a $50 fee. Still, that is also not worth it as the computer may not even be worth $50.
Here are some specifications:
80 GIG drive specs: SEAGATE BARRACUDA 7200.7 80GB hard drive
computer: imac G3 (slot loading version)
OS: Mac OS9
Thank you for any suggestions especially as to whether I should attempt to return the hard drive or look for a refund for this hard drive or attempt to reformat the drive and try again (backing up the data first).
I also question the source of all the data on my friends computer. If he had the original operating system disks (which he said didn't come with his computer when he purchased it second-hand), I could have easily re-installed the OS and the applications. But he doesn't have any disks. That serves me right for having to deal with trying to help out someone who has software from a questionable source. I'm never doing that again. I guess that makes me guilty too as an accomplice. I don't feel very good about this
I didn't know for sure - but I guess I should have assumed his software was illegal if he didn't have the disks - I was afraid to ask. I'm never putting myself in this possibly illegal situation again. Never again will I try to help someone out who doesn't clearly have the legal disks. Please forgive me and everyone else who reads this post. I feel shameful about this but somehow I must get myself out of this problem. I've learned a good lesson. Should I attempt to fix his computer? Or should I tell him to first buy a legal OS and software before I can help him out? You see I feel further guilt because I was the one who gave him the 80 GIG problematic hard drive that failed and I feel I should have to fix it. Can anyone offer me a bit of advice? What do I do?
What's the right thing to do?

Answer 1

Thank you Jim and Apple2Freak,
I appreciate your comments. I am now suggesting to my friend to buy a legal OS and if that is the case I am suggesting to him to move to OSX instead of OS9. Luckily he let me know there wasn't much data on that drive that he needed to save. I am still trying to determine if I could still use this hard drive with the keylength errors if I erase it or if the hard drive has permanent damage. I am hoping that I could install OSX on it and erase the hard drive to start again.
This imac (slot loading version) can support up to OS 10.3.9 however I might consider Xpostfacto to try to run 10.4. But then I would need to buy 10.3.9 as well as 10.4 and that would double my OS cost. I think I might just look for OS 10.3.9 only. Its not worth it for me to buy two OSes for it.
Jim, your post was very interesting because it also pointed out that it could be an issue of bad RAM. A few months ago we installed some new second-hand RAM and I wonder if that is the cause of all these problems. I will have to check that first.
Thanks again!