aes_calc: 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/lib/srtp/bin/aes_calc - from package: srtp-utils

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

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