deletepdfpage: 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/deletepdfpage - from package: libcam-pdf-perl

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

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