signtool: 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/signtool - from package: nss-tools

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

On Debian possible default full paths are:

/usr/bin/signtool - from package: libnss3-tools

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

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