url_handler.sh: 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/lib64/dx/bin/url_handler.sh - from package: dx
/usr/bin/url_handler.sh - from package: urlview

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

On Debian possible default full paths are:

/usr/lib/dx/bin/url_handler.sh - from package: dx

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

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