I recently reinstalled PS3 media server when i could not watch anything on my xbox360. Turns out someone had unupdated my xbox360 and i only needed to reupdate it which i did.
So it all worked fine. Next day after 20-120 secs depending on the file it just stops and says unplayable content. (If i use a usb key and put an XVID it will play so its not th e xbox codecs)
I am on win 7 64bit. i3 cpu @3.07ghz 4gb ram. Windows runs on SSD and ps3 mediaserver runs on an external usb HD.
Im using Mencoder but i pretty much tried all the other ones as well.