viewgam: 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/viewgam - from package: argyll

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

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