You'll have strange problems trying to backup active Virtual Machines.
Not every Backup Exec Agent can talk to every server. Here's the combinations that will work.
64 bit CPUs have been out for a while, but 64 bit Windows was only released in April 2005 (http://www.microsoft.com/presspass/press/2005/apr05/04-25Winx64LaunchPR.mspx). BE 10 was released in January 2005, so predates it. As a result, Backup Exec 10 (including 10d) are not supported on 64 bit Windows for the media server.