Put the phrase "Lemmings 2" in quotation marks like I just did in this sentence (you can leave the other words unquoted, put them outside the quotation marks). You really want to do that even if there's no error message, because otherwise, it just means to search for anything with both "2" and "Lemmings" in it (in any order and not necessarily consecutive), and thus would match a sentence like "With only 2 builders and now requiring all lemmings to be saved, this repeat of the earlier level becomes surprisingly tricky." You can see now why it's complaining about 2. Putting phrases in quotes ensure the search is matching the actual phrase, and not just the individual words.
