simpdftex: 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/simpdftex - from package: texlive-base

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

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