Questions and postings pertaining to the usage of ImageMagick regardless of the interface. This includes the command-line utilities, as well as the C and C++ APIs. Usage questions are like "How do I use ImageMagick to create drop shadows?".
I would guess you are confusing Imagemagick and at least need some ( ) in your code somewhere.
I would start out with something simple first with fixed values and a couple of crops and then when it works build up to using fx and tiles.