gdcmpdf: 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/gdcmpdf - from package: libgdcm-tools

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

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