Still same error. But some time I get M_MOD_RL_tile_.dll is not found error.Did you try calling MagickNET.Initialize without any parameters? And can you temporary move the method call to your Page_Load?
Note sureI noticed your vote on the 'Include all files in the dll' issue. I managed to get it to work and the next release will only contain the xml files from imagemagick and not the dll's. Maybe that will resolve your problems.