bvnc: 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/bvnc - from package: avahi-ui-tools

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

On Debian possible default full paths are:

/usr/bin/bvnc - from package: avahi-ui-utils

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

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