Microsoft Windows XP cannot read DVD disks that use the Universal Disk Format (UDF) 2. 5 0 defect management system ( Which is the used file system for HD DVD and AVCHD disks). When you view the DVD contents by using Windows Explorer, you see an empty root folder.
To be able to read these HD DVD disk, you have to install an UDF 2 driver. For more details please read the Microsoft Knowledge Base article: