ASWallpaper: 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/ASWallpaper - from package: afterstep

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

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