Have you tried StopDuplicates?
>> 21 October 2010
StopDuplicates is a Java Graphical application that l released to Free/Open Source some years ago (last update was on march 2009).
This program can easily locate and remove duplicates, based on MD5sums.
It's available in English, French and Spanish.
All you need is the .jar file and JDK installed on your machine (platform independent)
You can download program and source files
Enjoy !
http://apps.java-javafx.com/download.jsp