ended up with this
can i trim this down, or does it have to find it first, i select cell I1 each time, i try to keep away from selectin cells, but this would miss the first instance if i didnt (wouldnt it :s)
vb Code:
  1. Columns("I:I").Find(What:="#N/A", After:=ActiveCell, LookIn:=xlFormulas, _
  2.         LookAt:=xlPart, SearchOrder:=xlByRows, SearchDirection:=xlNext, _
  3.         MatchCase:=False, SearchFormat:=False).Replace What:="#N/A", Replacement:=unique_ref, LookAt:=xlPart, _
  4.         SearchOrder:=xlByRows, MatchCase:=False, SearchFormat:=False, _
  5.         ReplaceFormat:=False