Just to be clear, the dds.exe file is not something you run, it is something Gimp is supposed to run. In my case Gimp was installed to C:\Program Files\GIMP-2.0 and so I placed dds.exe inside C:\Program Files\GIMP-2.0\lib\gimp\2.0\plug-ins. Try doing a similar thing for your setup. After that, open Gimp and it should "just work."