What's the root cause for this error?

 

Below is the error screenshot.

Who knows the root cause and how to fix it?

 

Array Error 

 
Array is not properly coded.
 
jollydragon: Who knows the root cause and how to fix it?
  1. You are trying to access an element that does not exist in the array.
  2. Don't do it.
  3. Do you thing we are mind readers? We can't see your code.
 

Thank you both.

However, what does the '(91,115)' in the warning of the screenshot mean? 

 
It tells you where the error occurred. In your case, on Line 91 at 115 characters in.
 
honest_knave:
It tells you where the error occurred. In your case, on Line 91 at 115 characters in.

Dear Knave, thank you very much! It's a pity that I can't find the location as the codes were updated already.

Let me test again with the new codes.  

Reason: