vewarn: 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:

/lib/rc/bin/vewarn - from package: openrc

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