Well after closely looking into a strange problem I was having with the newest PS3 Media Server, I finally was able to fix it with some older codecs as a work around. Problem I was having I couldn't play any of my MKV's rather then give me a data corruption error.
As most people stated, 1.70 is the working one as it did for even me.
So I though to myself, it has to be a codec that's creating the problem.
So I went into the directory that PS3 Media Server is in, and copied / backed up the win32 folder which of course has all the older codecs and what not on it.
Uninstalled 1.70 and reinstalled 1.90.1 back on and copied / over wrote the win32 folder and walla, it worked. I am able to watch all movies // mkv's
So the steps:
1. Install 1.70, back up win32 folder
2. Uninstall 1.70
3. Install 1.90.1
4. Copy win32 overwrite files
5. Run and host / play
May or may not work for everyone, but did for me, and I hope it works for those that have same issue as I did.