fvconverter: 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/fvconverter - from package: fawkes-firevision-tools

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

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