Langley,
I've had no problems using lookups under recent versions of Windows, regardless of the Paradox version. However, I do follow certain design conventions appropriate for multiple versions of Windows and Paradox:
1. I limit my tablenames to the 8.3 conventions.
2. I store lookup tables in the same directory as data tables.
3. I use project aliases to refer to database locations.
4. I do not use UNC naming conventions to map to drives containing Paradox objects.
Now, as I posted in other threads, I have seen problems where you need to run the compatibility tool under XP and Win2K, depending on the version of Paradox being used, however, that's about the only quirk I've seen.
hope this helps...
-- Lance