I'm sorry to hear that you're having trouble with your TV.
The "File Not Supported" is noting that either the container, video codec, audio codec or resolution may not be supported. The chart listed in the owner's manual notes which containers support which codecs and resolutions for each file.
I have a samsung UA40B700, when I go into media player and select photos or video's, it displays the thumbnail but if I go into the video or picture to play on the full screen then I get an error "not supported file format", very frustrating because it the manual says it should play various format's that I have stored on my BlackArmor NAS device, music plays fine. I only have problems with Video and Photos? It does play some coppied DVD's
Current firmware is 2005.