There was an old issue that was fixed whereby you could end up with a situation like this:
When the wizard finished, the wallet would then get opened as normally. The wallet file would contain the new seed, new xpub, but old addresses.
It would appear that you might have had something similar happen... You should create a new wallet ("File -> New\Restore -> NEW_WALLET_NAME -> Standard wallet -> I already have a seed"), as suggested by nc50lc... and see if it generates the same addresses as the wallet that is giving you the corruption warning.
If it does not, then your seed will not be able to restore your wallet file. You should immediately create a new wallet (with new seed) and send all your Bitcoins from "corrupt" wallet to new wallet.
He should definitely attempt a restore but if his seed doesn't generate the same addresses he won't be able to send coins from the old to the new one. That's because the old wallet doesn't have the corresponding private keys/precursor seed either.