pdfmex: 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/pdfmex - from package: texlive-lang-polish

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

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