qtdbf: 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/qtdbf - from package: qtdbf

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

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