This problem is not unique to me, as I found from a post dated May 31. Unfortunately, he didn't get an answer posted, so I can't borrow his fix.
Occasionally (I love intermittent problems), the M100 will stop playing a clip and give me an error message reading "Could not play because the video data format is invalid" or "Could not play because the media was recorded with a newer version of Media 100i." Since I digitized this footage last night, I don't think this is the problem. Today, I'm getting both of the messages and have to force-quit the program to get the error screens to go away. When I re-launch M100, it will even come up with the error screen waiting for me.
This issue has surfaced before, and I've had to re-digitize the footage to get it to work properly, but is there any other fix for this? Usually, I've still got the original footage, but if I sourced it from somewhere else, that's not so good.
I appreciate all of the help you guys (and gals) provide here in the pasture.