osgterrain: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On Debian possible default full paths are:

/usr/bin/osgterrain - from package: openscenegraph

You may install the required package with command apt-get install {package}

Error in other languages:
osgterrain: bevel nie gevind nie
osgterrain: comandă negăsită
osgterrain: comando não encontrado
osgterrain: commande introuvable
osgterrain: command not found
osgterrain: käsku ei ole
osgterrain: không tìm thấy lệnh
osgterrain: komanda nerasta
osgterrain: Kommando nicht gefunden.
osgterrain: kommandot finns inte
osgterrain: komut yok
osgterrain: nie znaleziono polecenia
osgterrain: níor aimsíodh an t-ordú
osgterrain: no se encontró la orden
osgterrain: no s'ha trobat l'ordre
osgterrain: opdracht niet gevonden
osgterrain: parancs nem található
osgterrain: perintah tidak ditemukan
osgterrain: príkaz nenájdený
osgterrain: příkaz nenalezen
osgterrain: команда не найдена
osgterrain: командата не е открита
osgterrain: 命令找不到
osgterrain: コマンドが見つかりません