python2.6-vxi11-cli: 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/python2.6-vxi11-cli - from package: python-vxi11

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

Error in other languages:
python2.6-vxi11-cli: bevel nie gevind nie
python2.6-vxi11-cli: comandă negăsită
python2.6-vxi11-cli: comando não encontrado
python2.6-vxi11-cli: commande introuvable
python2.6-vxi11-cli: command not found
python2.6-vxi11-cli: käsku ei ole
python2.6-vxi11-cli: không tìm thấy lệnh
python2.6-vxi11-cli: komanda nerasta
python2.6-vxi11-cli: Kommando nicht gefunden.
python2.6-vxi11-cli: kommandot finns inte
python2.6-vxi11-cli: komut yok
python2.6-vxi11-cli: nie znaleziono polecenia
python2.6-vxi11-cli: níor aimsíodh an t-ordú
python2.6-vxi11-cli: no se encontró la orden
python2.6-vxi11-cli: no s'ha trobat l'ordre
python2.6-vxi11-cli: opdracht niet gevonden
python2.6-vxi11-cli: parancs nem található
python2.6-vxi11-cli: perintah tidak ditemukan
python2.6-vxi11-cli: príkaz nenájdený
python2.6-vxi11-cli: příkaz nenalezen
python2.6-vxi11-cli: команда не найдена
python2.6-vxi11-cli: командата не е открита
python2.6-vxi11-cli: 命令找不到
python2.6-vxi11-cli: コマンドが見つかりません