When loading you say it gets so far, watch the screen can you see the machmotion dialog load, at this point the mach core has already loaded so you know the core is fine.
Plugins are in there own right small applets that are loaded, even if not being used a part of them are loaded, I tend to remove any plugin I dont require.
Another way is to load straight into the screen editor, from the mach4 directory run Mach4GUI /e if you get into the screen editor this means there is something not right with the screenset that is being loaded.
DazTheGas