After installation I have a blank page when opening the catalog.

In your /INCLUDES/CONFIGURE.PHP file, enter/verify the following:

a. make sure your HTTP_SERVER info is set to properly reflect your server’s DNS name or IP address AND PORT NUMBER, if any. Even if you’re using “localhost” or your own IP address, if your server’s running on a port OTHER THAN the default of 80, you’ll need to specify it here:

define(‘HTTP_SERVER’, ‘http://mydomain.com:50000′;

(Should check the HTTP_CATALOG_SERVER line too)

b. make sure your server’s DIR_FS_SQL_CACHE is pointing to a VALID directory that your server has rights to write in.
If you’re running a Unix server, the default of /tmp might be OK. Or you might need to make it part of your store’s folders under /catalog/tmp, etc.
If you’re running a Windows server, try this instead:

define(‘DIR_FS_SQL_CACHE’, ‘c:/windows/temp’);

c. check to be sure the STORE_SESSIONS variable is set to your database type. (often the default of ‘db’ will work fine, but often testing it with ‘mysql’ is very valuable too)

define(‘STORE_SESSIONS’, ‘mysql’);