That is one of default tables of nopCommerce. Just check if you have that table available at your database. If yes, then suggest to contact with Nop-Templates directly or via Ticket/Board.
The issue is not that the table is missing but that the Ajax Filters SQL script is targetting the table with the default database schema (dto) whereas you probably have a different scheme on your database.
You can fix this issue by firstly, removing the ajax filters from the ~/App_Data/plugins.json file and restarting your store. After that go to the Administration -> Configuration -> Settings -> All settings (advanced) and add the following settings: Name: ajaxFilterSettings.DboSchema Value: [yourDatabaseScheme]
where your database scheme is your database scheme.
After that, go to the Administration -> Configuration -> Local Plugins page and try to install the Ajax Filters plugin again.