I did install gs916w32.exe and gs916w64.exe, not sure that those are the correct packages though? I am downloading your package now, and will create a scenario where I can get an error message I'm able to see/copy somehow, and provide that shortly...
Here are the results of version check on both versions...
C:\ImageMagick>convert -version
Version: ImageMagick 6.9.0-7 Q16 x86 2015-02-18
http://www.imagemagick.org
Copyright: Copyright (C) 1999-2015 ImageMagick Studio LLC
License:
http://www.imagemagick.org/script/license.php
Features: DPC Modules OpenMP
Delegates (built-in): bzlib cairo freetype jbig jng jp2 jpeg lcms lqr openexr pa
ngocairo png ps rsvg tiff webp xml zlib
C:\ImageMagick64>convert -version
Version: ImageMagick 6.9.1--6 Q16 x64 2015-06-20
http://www.imagemagick.org
Copyright: Copyright (C) 1999-2015 ImageMagick Studio LLC
License:
http://www.imagemagick.org/script/license.php
Features: Cipher DPC Modules OpenMP
Delegates (built-in): bzlib cairo freetype jng jp2 jpeg lcms lqr openexr pangoca
iro png ps rsvg tiff webp xml zlib