I also thought it might be something browers specific: I use Opera. I also tried to run the experiment in Internet Explorer, but the same error appeared (page was empty after loading).
But I tried it on two other computers with Firefox and Internet Explorer and it worked perfectly fine. So maybe it is a computer specific problem? I will ask some people to run the experiment and let you know if I could find out, if it’s just me facing this problem.
I am glad to hear that the CheckPreloaded() command is also working with zip-files!
Thank you for help!