Buildings page problem

Over the last few days (I was absent before that for several months), I've been experiencing problems with the Buildings page http://en.game.industrie-tycoon.de/gebaeude.php?sort=all. When I select multiple buildings and then click a button (such as 'choose product'), I get 'page cannot be found'. I usually end up needing to 'visit' each building to make my changes one by one.

I haven't seen anyone else mention this problem, so I think it may be a situation where the game and my browser just aren't getting along. I use Maxthon 1.6.3 (build 80) Unicode. I used this same browser before my absence without any problems, but perhaps some coding on the page was changed in the interim.

Win XP the home edition

If you can't reproduce it, then I wonder whether my security suite might be the real problem - I'm using a new one since I've been back. It's the CA Security Center, and I imagine either the firewall or filter in that package could be interfering. In that case, I'd probably need to get different ones in order to resolve this.