shift_lines: 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/shift_lines - from package: xviewg

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

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