I've found an alternate workaround because the above workaround--DRAC-IP/cgi/vkvm--doesn't work for me (my ISA is blocking operation of the VNC/VKVM): I have installed current versions of both Java 7 (currently 7u5) and Java 6 (currently 6u33). When I want to connect to the DRAC 4 console, I go to Windows Control Panel and click on the Java applet. When the applet opens, I click on the Java tab, and then View. Both Java 1.7 and Java 1.6 are enabled. I disable Java 1.7 (leaving Java 1.6 enabled), then click OK, then Apply. Now when I try to connect to the DRAC 4 console, Java 6 loads, and I can once again see the server desktop. When done, I return to the Java applet, disable Java 1.6 and re-enable Java 1.7.
GaryK