combinedeltarpm: 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 CentOS possible default full paths are:

/usr/bin/combinedeltarpm - from package: deltarpm

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/combinedeltarpm - from package: deltarpm

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

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