>I don't believe it's a duplicate key.
>
>The first key begins with P_ID

FOUND THE ERROR KEY:

SELECT PCategories && Table to append into
try 
 FIRST = RECCOUNT('PCategories'
 APPEND FROM DBF( "__NewPartCtg" )
catch
  select __NewPartCtg
  LOCATE
  SKIP RECCOUNT('PCategories')- M.first
   ? "fault key is ", P_ID + PARTICPCTG1 + PARTICPCTG2 + PARTICPCTG3
ENDTRY