Other posts have talked about this problem, that Prometric doesn't intend to fix the problem which is that if you go back to a drag and drop problem it will erase your previous answer (it's a feature!!!). BTW, about how many of these problems are there on the exam? It would be nice to know for strategy reasons. Thanks.
Perhaps a firewall blocks the site ? Ever since I put up the link to the 'Inquisition' format questions, traffic to the word document mock exam has decreased dramatically and traffic to the questions displayed in Inquisition format has increased. Try out the third link. Good luck with your exam