pyxplot_watch: command not found

Have You tried accessing the binary with the full path?

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/pyxplot_watch - from package: pyxplot

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