vboxbeep: 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 CentOS possible default full paths are:

/usr/bin/vboxbeep - from package: isdn4k-utils

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/vboxbeep - from package: isdnvboxclient

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

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