ASFileBrowser: 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/ASFileBrowser - from package: afterstep

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

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