Let's back it up a bit and understand carefully what's happening ..

For easy reference, I attach a link to a sample showing your posted data
with the earlier expression that I gave you implemented:

http://www.freefilehosting.net/download/3e988
Flagging Duplicates.xls

In the sample, the unique items are defined based on the fields in cols A to
C (that's what I gathered you specified earlier in your original thread). The
formula in D2**, copied down will flag uniques as FALSE, duplicates as TRUE.
Note that the source data need not be sorted for the flagging to work.

**In D2, copied down:
=IF(COUNTA(A2:C2)<3,"",SUMPRODUCT((A$2:A2=A2)*(B$2:B2=B2)*(C$2:C2=C2))>1)

To reconfirm our understanding:  
Uniques = 1st occurrence (FALSE)
Duplicates = 2nd occurrence onwards (TRUE)

And, any source lines with incomplete data for flagging (there must be data
in all 3 cols A to C) will return as blanks: "". This precaution is taken
care of by the front IF part in the expression: IF(COUNTA(A2:C2)<3,"",...