dbjoin: 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/dbjoin - from package: perl-Fsdb

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

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