When I was dropping my images into the Media and Folders and at the end of reading the Media I got this error. I looked through the application log but I could not find and errors.
The log file does indeed not contain any errors or warnings. But this is a log file is not the log file for which the errors were reported. This looks like a log file from a new session, IMatch has just started and loaded the database.
IMatch overrides the log file on every start, keeping the previous log file with the TX_ extension. This would have been the interesting one.
Probably it was just a problem reading an image anyway, so nothing to waste too much time on.