Error dotfuscating in the post-build process

Hi,

I'm trying to run dotfuscator in the VS2010 post build step and have followed this recipe:

http://msdn.microsoft.com/en-us/library/hh977082(v=vs.107).aspx

but when I reach the post build step I get an error saying:

"configuration file specified twice"

I only have one configuration file present in the root of the project folder.

Can someone please explain what might cause this error?

Thanks
Thomas, Retune-DSP