I am unable to download your file, it stops at 2.6mb. I used another CR2 image I found online and I got it to work. Did you place the dcraw.exe in the directory that contains delegates.xml and CORE_RL_Magick++.dll_? What is the result of:
using (MagickImage image = new MagickImage())
{
image.Verbose = true;
image.Read(path);
}