fbtv: 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/fbtv - from package: xawtv

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

On Debian possible default full paths are:

/usr/bin/fbtv - from package: fbtv

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

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