I am also having this same problem. I ran the java file and it found my PS3 as an "unknown device", and none of the engines loaded so I couldn't watch any videos. So, I quit the PMS. I then restarted it as the .exe file and it worked. I don't know if this action "kicked it into gear", though.
I was having all sorts of errors when trying to update to the current PMS version. Through restarting, uninstalling, re-downloading, etc. I eventually got the latest PMS to completely install properly.
I believe this issue is java related. I completely uninstalled all versions of java and reinstalled just the latest version.
Still this problem persisted. But I ran the pms.jar, it failed to load all my engines, I quit, then restarted the pms regularly and it worked fine.
After using it today, I quit the PMS and re-started it and got the same problem. And so this time I simply ran the pms.jar and THIS time it ran fine with all appropriate engines running.
This issue seems to have variations of behavior. For now I just created a desktop icon for the PMS.JAR file and am running it through that.
Here is my entry per the Problem Reporting Guidelines:
1. My computer specs:
Windows 7/32 bit/4GB ram (3.25 usable)/3.10GHz processor
PMS version: 1.81.0
Java Version: 7, update 21
2. Streaming to my PS3
3. wifi connection through Apple Airport Extreme, using a netgear external wifi card on my PC (I have to admit this thing has been giving me problems lately, dropping connection; and I often have to pull it out and plug it back in to get it to work)
4. No transcoding
5. What is not working: PMS not finding any renderers
6. debug.log is here: http://pastebin.com/raw.php?i=UcZXxNcu
7. No file specific info applicable.