GWCommand: 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/GWCommand - from package: afterstep

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