gt7cvt: 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/gt7cvt - from package: simh

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

Error in other languages:
gt7cvt: bevel nie gevind nie
gt7cvt: comandă negăsită
gt7cvt: comando não encontrado
gt7cvt: commande introuvable
gt7cvt: command not found
gt7cvt: käsku ei ole
gt7cvt: không tìm thấy lệnh
gt7cvt: komanda nerasta
gt7cvt: Kommando nicht gefunden.
gt7cvt: kommandot finns inte
gt7cvt: komut yok
gt7cvt: nie znaleziono polecenia
gt7cvt: níor aimsíodh an t-ordú
gt7cvt: no se encontró la orden
gt7cvt: no s'ha trobat l'ordre
gt7cvt: opdracht niet gevonden
gt7cvt: parancs nem található
gt7cvt: perintah tidak ditemukan
gt7cvt: príkaz nenájdený
gt7cvt: příkaz nenalezen
gt7cvt: команда не найдена
gt7cvt: командата не е открита
gt7cvt: 命令找不到
gt7cvt: コマンドが見つかりません