walmgr3: 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/walmgr3 - from package: skytools3-walmgr

You may install the required package with command apt-get install {package}
Error in other languages:
walmgr3: bevel nie gevind nie
walmgr3: comandă negăsită
walmgr3: comando não encontrado
walmgr3: commande introuvable
walmgr3: command not found
walmgr3: käsku ei ole
walmgr3: không tìm thấy lệnh
walmgr3: komanda nerasta
walmgr3: Kommando nicht gefunden.
walmgr3: kommandot finns inte
walmgr3: komut yok
walmgr3: nie znaleziono polecenia
walmgr3: níor aimsíodh an t-ordú
walmgr3: no se encontró la orden
walmgr3: no s'ha trobat l'ordre
walmgr3: opdracht niet gevonden
walmgr3: parancs nem található
walmgr3: perintah tidak ditemukan
walmgr3: príkaz nenájdený
walmgr3: příkaz nenalezen
walmgr3: команда не найдена
walmgr3: командата не е открита
walmgr3: 命令找不到
walmgr3: コマンドが見つかりません