I was streaming some videos on my PS3 today from my laptop, and I encountered this error. In case anyone comes across the same error I thought I'd post the fix.
It was pretty easy, it just took a while to realize what it was. I had downloaded some videos through torrents, and cancelled a couple of them before they had finished. The video files stick around even though they're not finished, so when I mass-copied them over to my video folders, it was causing Media Sharing to crash whenever I tried to view the files through the PS3. Then I realized it was causing Media Player to crash whenever I viewed my Videos Library. So, long story short, make sure you don't put any half-finished video files in your videos folder!
