I think occasionally it makes a mistake. You get the option to change the name of the file, so if you make any minor alteration you should be able to download it with no problem.

The files you are talking about should also have a green tick against them in the search window in place of the stars in the quality column. which indicates also that you have (supposedly) already got the file.

I hope this helps.

__________________
To get Phex Click on the Fox