db4-2-db5: 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 Debian possible default full paths are:

/usr/bin/db4-2-db5 - from package: publican

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

Error in other languages:
db4-2-db5: bevel nie gevind nie
db4-2-db5: comandă negăsită
db4-2-db5: comando não encontrado
db4-2-db5: commande introuvable
db4-2-db5: command not found
db4-2-db5: käsku ei ole
db4-2-db5: không tìm thấy lệnh
db4-2-db5: komanda nerasta
db4-2-db5: Kommando nicht gefunden.
db4-2-db5: kommandot finns inte
db4-2-db5: komut yok
db4-2-db5: nie znaleziono polecenia
db4-2-db5: níor aimsíodh an t-ordú
db4-2-db5: no se encontró la orden
db4-2-db5: no s'ha trobat l'ordre
db4-2-db5: opdracht niet gevonden
db4-2-db5: parancs nem található
db4-2-db5: perintah tidak ditemukan
db4-2-db5: príkaz nenájdený
db4-2-db5: příkaz nenalezen
db4-2-db5: команда не найдена
db4-2-db5: командата не е открита
db4-2-db5: 命令找不到
db4-2-db5: コマンドが見つかりません