simg2img: 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/simg2img - from package: android-tools-fsutils

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

Error in other languages:
simg2img: bevel nie gevind nie
simg2img: comandă negăsită
simg2img: comando não encontrado
simg2img: commande introuvable
simg2img: command not found
simg2img: käsku ei ole
simg2img: không tìm thấy lệnh
simg2img: komanda nerasta
simg2img: Kommando nicht gefunden.
simg2img: kommandot finns inte
simg2img: komut yok
simg2img: nie znaleziono polecenia
simg2img: níor aimsíodh an t-ordú
simg2img: no se encontró la orden
simg2img: no s'ha trobat l'ordre
simg2img: opdracht niet gevonden
simg2img: parancs nem található
simg2img: perintah tidak ditemukan
simg2img: príkaz nenájdený
simg2img: příkaz nenalezen
simg2img: команда не найдена
simg2img: командата не е открита
simg2img: 命令找不到
simg2img: コマンドが見つかりません