The file extention MPMP is not a default SQL extention, so probably it is generated by some other process. Can you see who created (is owner of) these files?

Perhaps a longshot, but this could give some information for you to sort out: http://serverfault.com/questions/29816/what-is-the-sqldump-file-for

Another possible option (again a longshot): some kind of export process (like: http://sqldump.sourceforge.net/) is extracting the data from the database to flat files on disk?