[Therion] Problem with kml-File for google Earth

Hi, I have a cave with a length from about 400m. It is shared into 8 separated *.th and *.th2 Files. All worked well, if I want to get a PDF-File with projection plan. But in the kml-File (made with: export map -fmt kml -projection plan -layout standard -output BTH-11-02-06_GS.kml) there are missing part 4 of the cave. Has anyone an Idea, where the problem could be? Many thanks Markus