I've been trying to insert some .mpg files into my project, but everytime I import them and drag them to the timeline, it just shows a red "Media content offline". Anyone knows why? It's not some link that got lost, it happens just after importing the files. Maybe it's the file format?...
The MPEG importer can be flaky at times. Try selecting the clip, right-clicking, and selecting "Link Media." Navigate to the same file, and select it and hit OK. This usually makes the MPEG clip stick; I don't know why it won't the first time.