For what it's worth, I found the answer to this problem. What happened was that upon import of the table files, Launchbox indexed the directb2s file, rather than the vpx file in the launch setting for the GAME. Again, this is a setting at the game level. So, for a game that is giving you the "Error loading ........\Tables\[tablename.directb2s" error, RIGHT click on the game in Launchbox, choose [Edit], [Edit Metadata/Media], and choose [Launching] in the left hand navigation pane. Then simply replace the (incorrect) "directb2s" extension with "vpx". I've attached a screenshot of a corrected setup.
Good Luck!