ostra-cg: 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 CentOS possible default full paths are:

/usr/bin/ostra-cg - from package: dwarves

You may install the required package with command yum install {package}

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