lbzmerge: 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/lbzmerge - from package: lbzip2-utils

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

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