I had trouble loading '.srt' files even though,the video and the subtitle file were of same name except for the extension.I couldn't get any other subtitle file.Got vexed ,but finally found a cool tool "Subtitle Workshop" which works like charm with fixing the files. All you have to do is open the damaged file even though errors pop up.Then you need to save the file again voila,file gets fixed.
Check the tool here :- Subtitle Workshop