mysecureshell: 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/mysecureshell - from package: mysecureshell

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

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