I just found out the hard way that VMWare Server 2.0′s Console plug-in does not work with Firefox 3.6.
Perhaps in the future VMWare will release a compatible plugin, but for now the fix is to use the console plugin for Internet Explorer, Firefox 3.5x or use VMWare Player 3.0.
The following error is what comes up in Firefox 3.6 or any other unsupported browser.
“Cannot access virtual machine console. The request timed out. The attempt to acquire a valid session ticket for MACHINE_NAME took longer than expected. If this problem persists, contact your system administrator.”