ossim-dem: 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/ossim-dem - from package: ossim-core

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

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