gnome-disk-image-mounter: 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 Debian possible default full paths are:

/usr/bin/gnome-disk-image-mounter - from package: gnome-disk-utility

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

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