p7verify: 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/p7verify - from package: libnss3-tools

You may install the required package with command apt-get install {package}
Error in other languages:
p7verify: bevel nie gevind nie
p7verify: comandă negăsită
p7verify: comando não encontrado
p7verify: commande introuvable
p7verify: command not found
p7verify: käsku ei ole
p7verify: không tìm thấy lệnh
p7verify: komanda nerasta
p7verify: Kommando nicht gefunden.
p7verify: kommandot finns inte
p7verify: komut yok
p7verify: nie znaleziono polecenia
p7verify: níor aimsíodh an t-ordú
p7verify: no se encontró la orden
p7verify: no s'ha trobat l'ordre
p7verify: opdracht niet gevonden
p7verify: parancs nem található
p7verify: perintah tidak ditemukan
p7verify: príkaz nenájdený
p7verify: příkaz nenalezen
p7verify: команда не найдена
p7verify: командата не е открита
p7verify: 命令找不到
p7verify: コマンドが見つかりません