Virtual Server: VM's not starting

Virtual Server has a Administration Website, from where you start VM's. It seems that the site does not work on IE8 or FireFox 3 for some operations, starting VM's being one of them (another: changing virtual hard disk type from IDE to SCSI). The IE status bar showed "Error on page", just like when you load a page with JavaScript errors on it. Well, I'm not sure what was going on, but if you select the Compatibility View mode on IE, the page runs ok.