Array Formula Error Message

I have a workbook with a lot of array formulas that I have been using for over a year. I did go in the other day and change the rows that it looks to in the workbook that it looks to from 1-5000 (it was 1-3000). I am now getting an error message "the text string you entered is too long. Reduce the number of characters used or cancel the entry". It seemed to work fine until today. It will not let me change anything now because each time I select a cell that message comes up so even if I needed to change something it will not allow it. Thanks in advance for advise