Quicktime Missing Mime Types


The MIME types are missing from my Quicktime prefs; no list, only a blank white screen. I cannot play any midi files, or mpgs, etc. from the web.

I have tried reinstalling (7.0.1), and reverting to 6.5.2, and then reinstalling 7.0.1, but the problem remains. I've even tried copying Quicktime files from another computer to replace mine, but no luck.

Others seem to be having the same problem, but I haven't seen any solution. Can you help, please?

I'm running OS 10.3.9.