gamma.itt: 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/lib/eso-midas/13SEP/systab/bin/gamma.itt - from package: eso-midas

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

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