mtst-int64: command not found

Have You tried accessing the binary with the full path?

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/mtst-int64 - from package: scotch

You may install the required package with command apt-get install {package}
Error in other languages:
mtst-int64: bevel nie gevind nie
mtst-int64: comandă negăsită
mtst-int64: comando não encontrado
mtst-int64: commande introuvable
mtst-int64: command not found
mtst-int64: käsku ei ole
mtst-int64: không tìm thấy lệnh
mtst-int64: komanda nerasta
mtst-int64: Kommando nicht gefunden.
mtst-int64: kommandot finns inte
mtst-int64: komut yok
mtst-int64: nie znaleziono polecenia
mtst-int64: níor aimsíodh an t-ordú
mtst-int64: no se encontró la orden
mtst-int64: no s'ha trobat l'ordre
mtst-int64: opdracht niet gevonden
mtst-int64: parancs nem található
mtst-int64: perintah tidak ditemukan
mtst-int64: príkaz nenájdený
mtst-int64: příkaz nenalezen
mtst-int64: команда не найдена
mtst-int64: командата не е открита
mtst-int64: 命令找不到
mtst-int64: コマンドが見つかりません