Hi Psygorn, CustomUi and FxGraph are different things, one is a UI mod that adds several buttons on the bottom toolbar and the other is a plug-in command.

For installing CustomUI see here for where to copy the files:
http://moi3d.com/forum/index.php?webtag=MOI&msg=6507.452

For FxGraph unzip it and copy the files into the MoI appdata commands folder, it's in the same location as described in the above link for CustomUI as well.

- Michael