Are you using the advanced download package for this? Manually moving that stuff around and configuring it may work, but it is much better to use the advanced package to do the "advanced" install.
This is from the moving your site to a new server documentation, but it might be a good idea to check all the same files for the advanced install. The login loop as you're describing is often caused by these files containing incorrect paths.
http://rtfm.modx.com/display/revolution20/Moving+Your+Site+to+a+New+Server
Updating your Config Files
Once you've deployed files to the new server, you need to update the main configuration file: core/config/config.inc.php. You have to update paths to 6 different resources. Open the file and update the values for the following variables doing a find and replace:
/* PATHS */
$modx_core_path= '/path/to/modx_doc_root/core/';
$modx_processors_path= '/path/to/modx_doc_root/core/model/modx/processors/';
$modx_connectors_path= '/path/to/modx_doc_root/connectors/';
$modx_manager_path= '/path/to/modx_doc_root/manager/';
$modx_base_path= '/path/to/modx_doc_root/';
$modx_assets_path= '/path/to/modx_doc_root/assets/';
/* HOST (used for command-line PHP stuff) */
$http_host='yoursite.com';
If you are also moving your site into or out of a subfolder, be sure to update the variables such as $modx_connectors_url, $modx_manager_url, and $modx_base_url. They should generally
end with a slash (e.g., $modx_base_url='/' for a site not in a subfolder).
Permissions
Before you can edit your config file, you may need to loosen up the permissions. After you've edited it, be sure you restore the read-only permissions on the file.
There are also 3 additional configuration files that contain two PHP constants:
define('MODX_CORE_PATH', '/path/to/modx_doc_root/core/');
define('MODX_CONFIG_KEY', 'config');
/config.core.php
/connectors/config.core.php
/manager/config.core.php
Make sure you update the paths in these files as well.