Firefox works.

I haven't upgraded IE consciously, but of course Microsoft updates all the time in the background. If nothing on the site has changed, then something in IE has, creating an incompatibility.

Although my posts have been almost ignored in the Vendors Support forum, this seems to me like a urgent problem. How many casual users, even potential vendors, are going to be put off by this? Not everyone will be willing to install a second browser just to use Renderosity. Give it a try, doesn't work, move on...

IMP.