dump_xsettings: 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/dump_xsettings - from package: xsettingsd

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

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