aepanel: 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/aepanel - from package: aewm

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