See this Comm Center thread by Sascha Schuller.
-If i try to save a plan as RTML file the attached window appears and Planner crashes after that.
-If i try to import a plan that i had successfully saved as a ACP Plan (.txt) the second window appears, and Planner crashes again.
A normal ACP Plan works without problems (only the small issue ACP can't read the cooler tolerance transmitted by the plan.)