VBA Code works initially but not when I reopen the spreadsheet

I found this great code to let users add a name to a table.  It asks the user if they want to add the item, they say yes and then it adds it to the list and sorts it alphabetically.  It is great until I close and reopen the spreadsheet.  Then, I only get the error box on the top left corner of the cell.  It doesn't do any of the above.  Why won't it work when reopened?  I have tried recreating the spreadsheet twice with the exact results.  Nothing changes on the code when I look at it so I don't think that is it but I only know enough about code to be dangerous.