tdbbackup: command not found

Have You tried accessing the binary with the full path?

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/tdbbackup - from package: tdb-tools

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