Unable to play any .mp4 videos from shared computer

This used to work. For some reason, now I can see the files I want to play in the folder on the shared media server, but when I select them I get the message about unsupported file type. They are all .mp4’s and they used to play just fine on the WDTV live plus box. They still do on the computer. I saw a solution about powering the box off/on but that did not help.

Anyone have anything else to try?

The firmware is 1.06.42_B. which is the latest.

Thanks,

EZ