There should be an update for version 4.2.2. Can you try updating? It might solve the problem.
Have you taken a look at this page? There might be a solution there that works for you.
If you are interested, the settings are stored in the
wp_options table. If you search for all fields that contain (%LIKE%)
wprss_settings, you will find all the settings used by the plugin.
The feed sources and feed items are custom post type
wprss_feed_item respectively. All data that the plugin adds to them is stored as post meta.
However, I do not encourage that you modify the settings. They are the settings that can be found from RSS Aggregator > Settings. As for the post types, you can check if perhaps the items are in fact being imported into your database, but not shown in your WordPress admin. If that is the case, we will need to debug this further.
Also, we are about to release an update that fixes some importing problems when feeds update every (or less than) 10 minutes. It might help solve your issue.