gvfs-tree: 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/gvfs-tree - from package: gvfs

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

On Debian possible default full paths are:

/usr/bin/gvfs-tree - from package: gvfs-bin

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

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