xml2: 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/xml2 - from package: xml2

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

On Debian possible default full paths are:

/usr/bin/xml2 - from package: xml2

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

Error in other languages:
xml2: bevel nie gevind nie
xml2: comandă negăsită
xml2: comando não encontrado
xml2: commande introuvable
xml2: command not found
xml2: käsku ei ole
xml2: không tìm thấy lệnh
xml2: komanda nerasta
xml2: Kommando nicht gefunden.
xml2: kommandot finns inte
xml2: komut yok
xml2: nie znaleziono polecenia
xml2: níor aimsíodh an t-ordú
xml2: no se encontró la orden
xml2: no s'ha trobat l'ordre
xml2: opdracht niet gevonden
xml2: parancs nem található
xml2: perintah tidak ditemukan
xml2: príkaz nenájdený
xml2: příkaz nenalezen
xml2: команда не найдена
xml2: командата не е открита
xml2: 命令找不到
xml2: コマンドが見つかりません