I have a Mac tower and a newer Macbook, both with what I believe are identical versions of Finale 2011 and VDL 2.5. But on the Macbook, the only percussion MIDI maps showing in the instrument list are the VDL lite versions, the ones I believe built into Finale.

Is there a file I need to copy over to my laptop for this to work correctly, or some other remedy?

If you're using a score from [url=http://www.thewritescore.com/forum/]The Write Score[/url], you probably need to copy the appropriate xml files according to their documentation on the machine you're not seeing them on. Check the documentation that came with your template.