Everything seems good with your code. In your code, you uncommented the next 5 tests, which give some noise when reading test results:
But you modified only one test:
So, we think that you should comment out others. Below are the changes:
Console.WriteLine("Please enter query phrase:");
string query = Console.ReadLine();
SearchResult result = index.Search(query);
Console.WriteLine("Query: " + query);
Console.WriteLine("Documents: " + result.DocumentCount);
Console.WriteLine("Occurrences: " + result.OccurrenceCount);
Please have a look at the query language specification here. Secondly, are you evaluating the API in trial mode (without any license, even the temporary license)? You may face some limitations in that case. Have a look at the API evaluation limitations. However, you can avail a temporary license here.
If issue persists, please send us a screencast/video.