psktool: 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 CentOS possible default full paths are:

/usr/bin/psktool - from package: gnutls-utils

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/psktool - from package: gnutls-bin

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

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