thunar: 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/thunar - from package: Thunar

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

On Debian possible default full paths are:

/usr/bin/thunar - from package: Thunar

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

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