dot2gxl: 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/dot2gxl - from package: graphviz

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

On Debian possible default full paths are:

/usr/bin/dot2gxl - from package: graphviz

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

Error in other languages:
dot2gxl: bevel nie gevind nie
dot2gxl: comandă negăsită
dot2gxl: comando não encontrado
dot2gxl: commande introuvable
dot2gxl: command not found
dot2gxl: käsku ei ole
dot2gxl: không tìm thấy lệnh
dot2gxl: komanda nerasta
dot2gxl: Kommando nicht gefunden.
dot2gxl: kommandot finns inte
dot2gxl: komut yok
dot2gxl: nie znaleziono polecenia
dot2gxl: níor aimsíodh an t-ordú
dot2gxl: no se encontró la orden
dot2gxl: no s'ha trobat l'ordre
dot2gxl: opdracht niet gevonden
dot2gxl: parancs nem található
dot2gxl: perintah tidak ditemukan
dot2gxl: príkaz nenájdený
dot2gxl: příkaz nenalezen
dot2gxl: команда не найдена
dot2gxl: командата не е открита
dot2gxl: 命令找不到
dot2gxl: コマンドが見つかりません