Can't install drupal modules

After installing with no problems in vista (default directory) the bitnami drupal stack, i am trying to install the modules.
After extracting the file and asks me to choose a directory to install them, i choose the folder that the stack is installed. But it stops the setup procedure and gives this message "do not seems to contain a valid installation of bitnami wampstack the file properties.ini missing ".
I tried all the directories but i didnt found a solution.

Hi,

You can install any BitNami module over BitNami WAMP Stack not over BitNami Drupal Stack. Try to install the WAMP Stack and then the Drupal or a different BitNami module.

You mean that the bitnami modules are not extra modules for drupal installation, but the drupal instalation for wamp stack?
If you are right i feel soooo stupid :(

Do not feel stupid, we have to improve our documentation to clarify this. You can download two flavors of any application: the Stack which ships the servers and dependencies, everything to work on your computer, and the module, which you have to install on a BitNami platform: WAMP Stack or Ruby Stack.