cube_merge: 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/cube_merge - from package: cube

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

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