Don't download sample mod maps as they usually contain all kinds of "good stuff" the author wants you to have and quickly gets outdated. Instead just create sample terrain by yourself from the latest up to date game data available, anytime.
- start giants editor v8.1 (final)
- file -> new mod from game -> map: sample mod map 1
- delete all transformgroups with original terrain objects in them, basically only leave terrain and careerstartpoint
- save and exit
You can of course leave the objects from mapDE or mapUS (depending which you chosen) into the sample terrain, but usually they are just in the way and its easier to delete all of them.