Hi,
do a search in this formus and you will see a lot of info about Xbox360 streaming
but heres a few "rules" for it to work
1. Activate UPnP in DNS-323
2. dont share the root... create a folder and share that Folder
3. Make sure that the path from the Folder you are sharing to the movie file name are less than 70 characters
4. Do not use any special charater... limit yourself to:
letters - numbers - spaces - hyphens (-) - underscores (_) and periods (.)
5. once everything is named correctly - login to the DNS-323 GUI and "refresh" the UPnP listing
you should be able to see the folders and files
remember also that the 360 CAN NOT play all type of media.