Tester Error: "tester cannot calculate prices"

 
Hello, can somebody please explain what this error message means and what I need to do to get rid of it because MT4 tester doesn't work at the moment. Thanks
 
I think that I've discovered what the problem is - a lack of data for the dates being tested. It would help if the error explanations were a little more succinct because it seems to have confused a lot of people including me for a while.
 

Hi,

I am also getting the error as "Tester cannot calculate prices.Is there any help me on this error.

Few days before, my code worked fine for the same dates for which i tested.But now its not working.

Reason: