Thanks a lot mate. Your help is well appreciated, and it did help quite a few people over the last weeks!
But it should not be necessary to use a fix anymore, if you download the corrected v0.8.2 from:
http://www.global-explorer.de/contentpage_download.html
I have exchanged terrain.gml with a corrected version in ESRI shapefile format - and no other changes were made.
I have tested a few times with the new viewer release, and it worked.