Easy way is to connect to mysql and update ezuser table password field for admin login with some known password hash (e.g. from other user where you know password)
Also you many yet need to install eZ Components first before being able to clear cache, etc.
<i>http://ezcomponents.org/docs/install</i>
The situation you describe is very familiar result of not having components installed and available to php. I would suggest trying to install it via the pear method.
The issue you describe (missing components installation) also affects current eZ Publish 4.0.1 BitNami Installers. It seems you have to install components by hand (no BitNami Installer dependency for eZ Components I guess).