disc corruption on cold boot

[ffchinote]

I don't see how this is happening, but 4 times now I have had to restore my HD from my SD clone after a cold boot. Never from a restart such as Software updates, but after a power outage or a vacation shut down. I have a UPS so the machine I think was shut down properly the 2 times it was due to an outage. Is it at all likely that it is a software issue related to restoring from a cloned backup. Is an Archive install better after a disc corruption. I use erase and copy , not SU. Restore verifies from install disc. Trying to convince Apple it could be hardware but they insist on a A/I or clean install (PIA) is needed to be sure. Does this sound familiar to anyone? Running 10.4.11 on intel iMac. error is "invalid node structure" in DU. Apple boards gave one response to verify clone with DiscWarrier. Don't have it, but my BDay is soon even though I was hoping for Leopard.
Thanks