Apple Tv 2 DLNA support
Can the Apple TV 2 stream video from a media server that is DLNA capable?
Unfortunately no.
AppleTV2 is dependent on iTunes for local media streaming and content must be in a compatible format:
http://www.apple.com/appletv/specs.html
Note - even network solutions advertising an iTunes server do not work as they only support basic sharing not Home Sharing required by AppleTV2.
(you may hear of hacks/modifications to allow other usage but these are not officially supported/endorsed by Apple and cannot be discussed in detail here.)