I had the same experience as technomustang with both the version of the file downloaded from the web and with a backup copy of the file I had on my hard disk.

Wasn't using my computer today so tried leaving the file loading for a long period of time - almost three hours in the case of the backup.

Nothing has obviously changed except for a couple of Java and IE updates - and the file is the same one that did run in March. But apparently something in my system changed enough to kill things completely.

Looks like the web page applet versions of Alice worlds are the worst kind of buggy software - programs that stop working without any indication or obvious reason.