Sorry about making you wait this long for a reply... but someone else will probably have similar issue so:
If all the objects on the map drops below ground level, or is hanging in the air then you made changes to some parameters?
something like ..GeometryTemplate.yScale (see elsewhere for documentation)
It changes what ONE value in heightmap means in distance.. (1cm vs 100meters)
But its also quite likely that your operating system might not allow BF1942 write access to update the file, so you save your
changes but no error is displayed.. everything looks awesome until you restart the app and the changes are gone... because it was never saved.
(have a chat with your operating system's security officer..)
and/or this could also be the cause:
viewtopic.php?f=6&t=15739