unlzma: 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/unlzma - from package: xz-lzma-compat

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

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