We ran into the same error. We didn't realize that our orginal export ended unsuccessfully due to running out of disk space on our workstation hard drive and caused an imcomplete export to take place. We reran it with proper disk space and it ran successfully. Then the import worked as well.
Also, another thing. If you .dat file is not too big, you can open it open and see in the first couple of lines were it says set version DAM 8.X.X. For some reason, due to the imcomplete export, the DAM version won't be the right number. You can update the DAM version number to the correct value by comparing a "good" .dat file and you should overcome it.