Not a great start to 2007 as my M100i won't launch! The icon just bobs in the dock and then I get an error message 30870. I had the same problem a while back and it went away (mysteriously!) and now it's back.
I can launch M100 from a backup drive so it's not a hardware problem. I've tried verifying permissions and cleaning/optimizing the system using Onyx but no luck.
It was fine a few days ago and I've done noting since except encode some files in MPEGStreamclip and Compressor and use DVDSP a couple of times.
I would really like to know why this is happening - it looks like something is not being seen or initializing properly.
Try creating a new user on your system and look if Media 100 starts there. If yes, then it is a preference problem on your local user, or a problem with a 3rd party plugin. If it does not start, try reinstalling Media 100. Usually this cannot hurt at all, and maybe it fixes your problems.