gconf-merge-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/gconf-merge-tree - from package: GConf2

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

On Debian possible default full paths are:

/usr/bin/gconf-merge-tree - from package: GConf2

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

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