Ok, here's my code, with the dubg stuff included:
The resulting text file shows all status codes as zero.

And I'm still getting the error.

Any ideas?

***** DEBUG CODE *****
nHandle = FCREATE("c:\debug_info.txt")

FOR nField = 0 TO oDetailRec.Fields.Count - 1

  cInfo = oDetailRec.Fields(nField).Name + " - " + ;
          TRANSFORM(oDetailRec.Fields(nField).Status) + " - " + ;
          TRANSFORM(oDetailRec.Fields(nField).DefinedSize) + " - " + ;
          TRANSFORM(oDetailRec.Fields(nField).ActualSize) + " - " + ;
          "'" + ALLTRIM(TRANSFORM(oDetailRec.Fields(nField).Value)) + "'"
  
=FPUTS(nHandle, cInfo)

ENDFOR
=FCLOSE(nHandle)
***** DEBUG CODE *****

** Save the record
oDetailRec.Update()