Trouble with my SNG spreadsheet

[Focused]

Hi, I've been using the Aleomangus spreadsheet to record my results. I like the layout and was happy with it. The problem is I've reached upto around the 850th SNG and the formula seemed to have stopped working. I realise I downloaded it for free and would be willing to pay for an updated bug free version or replacement. Anyone else had this problem and any advise on what spreadsheet to use. Cheers.