em_pscan: 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/em_pscan - from package: emboss

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

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