I had the exact same problem... nearly pulled my hair out over it.
Can't load 'C:/Perl/site/lib/auto/Image/Magick/Magick.dll' for module Image::Magick
Then I remembered a note we had in our wiki, and sure enough -- I found the answer on the ImageMagick site itself:
If you have any problems, install theVisual C++ 2008 RedistributablePackage (x86) or Visual C++ 2008Redistributable Package (x64). 64-bitWindows requires both packages (x86 &x64).
Installed vcredist_x86.exe and all was well. :::phew!:::