dbunit: 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/dbunit - from package: php-phpunit-DbUnit

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

On Debian possible default full paths are:

/usr/bin/dbunit - from package: phpunit-dbunit

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

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