Oh man, this is a classic bad neighbour hood story
Why would you want to link to a shareware site, the hunting ground of spammers and scammers!
Just thinking out loud, I wonder if you have got yourself on some kind of blacklist due to the previous association? From what Ive heard, site adviser picks up from all the phishing and spam blacklists.
If your clean, you need to contact Macafee and find out more info. Be interested to hear how this pans out for you. Getting a public black mark can be a nightmare for any online business.