fspanel: 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/fspanel - from package: fspanel

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