Community Tip - Did you know you can set a signature that will be added to all your posts? Set it here! X
Have you tried putting aptspell.xml in the Arbortext-path\custom\dictionaries subdirectory?
From help: The custom\dictionaries path is automatically prepended to the dictionaries path at startup. Putting your user-defined dictionaries in the custom\dictionaries subdirectory makes them automatically available, avoiding manual steps to add them to the path.