"WordPress database error"

In your database the referal_url field of the wp_dwpc_impressions table is set to not be NULL, and at the moment of adding a record you try to set this field for the new record to NULL.
I see two options to solve this:
1. Avoid setting ‘referal_url’ to NULL:
INSERT INTO wp_dwpc_impressions (id, text_id, filtered, time_created, wp_post_id, dwpc_visitor_id, dwpc_last_impression_id, ip_address, impression_url, referal_url) VALUES (NULL, ‘ogTxAFr’, ‘0’, ‘2016-01-17 23:42:14’, ‘0’, ‘0’, ‘32129’, ‘73.200.219.200’, ‘http://mpjj.pw/&#8217;, NULL) <- This value NULL shouldn’t be actually NULL.
2. Access your database (you can do it via phpMyAdmin or any other database client) and modify the field ‘referal_url’ so it can hold a NULL value. For this you can use the following query in the SQL console for your database:
ALTER TABLE wp_dwpc_impressions MODIFY referal_url VARCHAR(200) NULL;