Just in case:
Make sure you are in a directory without symbols like "$%&/ etc. Best to keep directory name short and simple.
Make sure you are draging and droping the files to the raw2dng
Today my crystal ball is down so would you mind providing us more information like
Camera model
build (I guess date is ok)
Where did you get the build
Where did you get the raw2dng
Date the raw2dng was generated.
OPERATING SYSTEM
And.. please read this:
How To Ask Questions The Smart Way
http://www.catb.org/~esr/faqs/smart-questions.htmlAny other additional info would be useful for developers to trouble shoot something like this.