I cannot access price levels, multiple warning messages in the dashboard

The “price levels” plugin is installed, but it is not in the menu. Price levels are active, yet they cannot be modified or added to.

Also, there is a bunch of warnings in the Sunshine dashboard:

Warning: unserialize() expects parameter 1 to be string, array given in /hermes/walnacweb03/walnacweb03am/b29/irakly/clients/wp-content/plugins/sunshine-analytics/analytics.php on line 394

Warning: A non-numeric value encountered in /hermes/walnacweb03/walnacweb03am/b29/irakly/clients/wp-content/plugins/sunshine-analytics/analytics.php on line 413

Warning: A non-numeric value encountered in /hermes/walnacweb03/walnacweb03am/b29/irakly/clients/wp-content/plugins/sunshine-analytics/analytics.php on line 413

Warning: A non-numeric value encountered in /hermes/walnacweb03/walnacweb03am/b29/irakly/clients/wp-content/plugins/sunshine-analytics/analytics.php on line 413

Warning: A non-numeric value encountered in /hermes/walnacweb03/walnacweb03am/b29/irakly/clients/wp-content/plugins/sunshine-analytics/analytics.php on line 413

Warning: unserialize() expects parameter 1 to be string, array given in /hermes/walnacweb03/walnacweb03am/b29/irakly/clients/wp-content/plugins/sunshine-analytics/analytics.php on line 394

Warning: A non-numeric value encountered in /hermes/walnacweb03/walnacweb03am/b29/irakly/clients/wp-content/plugins/sunshine-analytics/analytics.php on line 413

……

Warning: A non-numeric value encountered in /hermes/walnacweb03/walnacweb03am/b29/irakly/clients/wp-content/plugins/sunshine-analytics/analytics.php on line 574

Warning: A non-numeric value encountered in /hermes/walnacweb03/walnacweb03am/b29/irakly/clients/wp-content/plugins/sunshine-analytics/analytics.php on line 574

The page I need help with: [log in to see the link]