Why is it that rockport shoes squeak?

Don't know why - tried all the suggestions, baby powder, lotion etc but nothing works. Made the mistake of buying a pair of black and an identical pair of brown Eastbourne Rockport's. They were recommended due to my Achilles tendon problems. Both left shoes started to squeak like a bag full of mice shortly thereafter. The problem seems to be very prevalent as I found out when I googled it. Waste of time making a really great pair of shoes if the noise stops the buyer from wearing them in public and certainly stops you from buying another pair. :(