compress-dummy: 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/compress-dummy - from package: sharutils

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

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