tstclnt: 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/tstclnt - from package: libnss3-tools

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

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