gnome-open: 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/gnome-open - from package: libgnome

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

On Debian possible default full paths are:

/usr/bin/gnome-open - from package: libgnome2-bin

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

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