First, as the "Announcement!" on the top of the "overview" page for this forum says, "read this before posting questions".
Ok ... as you've given virtually nowhere near enough info to make an educated guess, here goes a WAG ... it's an AVCHD file that is perhaps "missing" the other files needed for any playback system to re-assemble the full audio/video program. Either way, it's missing the REST of the bits needed to run in your system.
More info would always be helpful ... and polite?
Neil