xpra_launcher: 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/xpra_launcher - from package: xpra

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

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