not sure where the warning is coming from- will check the next time it appears- but I was running Classic 9 - on which I have my old photoshop - as well as LW on OS X so maybe that did it- ;-)
Also, my download window now predicts it's going to take 4 minutes to finish downloading LW.dmg (from the official site - just in case the version I got and paid for has issues - whereas before it was predicting 20 hours!!! Weird!!!!