bug in debug mode

In the plugin settings, I have this error :
Notice: Undefined index: excerpts in D:\wamp\www\wordpress391\wp-content\plugins\q-and-a\admin\q-a-plus-admin.php on line 308

And this :
Notice: Use of undefined constant search – assumed ‘search’ in D:\wamp\www\wordpress391\wp-content\plugins\q-and-a\admin\q-a-plus-admin.php on line 320

And this :
Notice: Use of undefined constant jquery – assumed ‘jquery’ in D:\wamp\www\wordpress391\wp-content\plugins\q-and-a\admin\q-a-plus-admin.php on line 368

https://www.ads-software.com/plugins/q-and-a/