Can a corrupt OS on a back-up drive cause kernel panics?

This is really strange and I could use some opinions.

Running an AGP G4, 1.3MHz, 1.5Meg of RAM and OS 10.4.10
About four weeks ago, out of the blue, I started to get kernel panics - one after the other.
I made another back-up with SuperDuper and then started checking memory, deleting some apps I had loaded and a few other things. All without success.
So I finally decided to re-install OS X and the problems just vanished.

The Mac was zipping along again, no more Kernel panics or other problems.

Now, yesterday and today, the Mac started to act funny - the cursor would freeze, videos would crash and kernel panics were back. Some of them I got just at the end of the boot up cycle, others at odd times. Reminded me of the Windows machine at the office.
So I ran the memory test, that seemed to be OK.
Then I booted off the OS X disk and repaired permissions and repaired each one of the volumes - two internally and 5 externally.
Repair was not necessary on any of the seven volumes, they all passed.
Permissions were repaired on the two internal volumes but when I ran "Repair Permissions" on the external volume where I had made a backup after I had all these kernel panics four weeks ago, about 1/3 through the repair cycle, everything just vanished from the screen and I was left with just a blue screen - no icons nothing.
I shut down the Mac and restarted - kernel panic at the end of the boot cycle.
Then I turned off the external drive that had the "corrupt" back-up on it and restarted. Everything worked fine.
Plugged the external drive back in and deleted the back up with the corrupt OS (from 4 weeks ago) and suddenly the Mac runs very much faster, really snappy and so far no more issues.

Long story but I thought the background was relevant.

Question: Is it possible that a corrupt OS on an external FW drive was causing these problems? Hard for me to understand since I never tried to boot off that drive so I thought it would have no bearing on what was going on with my main drive.