envfrom2srs: 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/envfrom2srs - from package: python-srs

You may install the required package with command apt-get install {package}
Error in other languages:
envfrom2srs: bevel nie gevind nie
envfrom2srs: comandă negăsită
envfrom2srs: comando não encontrado
envfrom2srs: commande introuvable
envfrom2srs: command not found
envfrom2srs: käsku ei ole
envfrom2srs: không tìm thấy lệnh
envfrom2srs: komanda nerasta
envfrom2srs: Kommando nicht gefunden.
envfrom2srs: kommandot finns inte
envfrom2srs: komut yok
envfrom2srs: nie znaleziono polecenia
envfrom2srs: níor aimsíodh an t-ordú
envfrom2srs: no se encontró la orden
envfrom2srs: no s'ha trobat l'ordre
envfrom2srs: opdracht niet gevonden
envfrom2srs: parancs nem található
envfrom2srs: perintah tidak ditemukan
envfrom2srs: príkaz nenájdený
envfrom2srs: příkaz nenalezen
envfrom2srs: команда не найдена
envfrom2srs: командата не е открита
envfrom2srs: 命令找不到
envfrom2srs: コマンドが見つかりません