matchbox-panel: 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/matchbox-panel - from package: matchbox-panel

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

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