Go to LW's menu bar, Tools -> Options -> Filters .. check keyword filters & make sure .lit is not listed. Also check extensions & make sure .lit is not listed. If it is listed as being filtered out then select it & click the remove button.

I can't test about finding .lit files at present since I'm overseas, but will try in over a week's time after I return. There are of course alternatives to .lit depending on what topical files you are after.