If you click on the "Help" menu what does it show as your "File Version #"? I can look at that and see if the updates after that include changes to the MileSplit results export.
Last year when MileSplit changed the format they accept it caused a handful of 'fixes' in the software to get it working somewhat reliably. It was pretty frustrating from my side because I kept getting conflicting and incomplete information on exactly what they wanted. Finally one of their developers got involved and provided very clear direction and answers then the uploads were accepted pretty consistently.
If you want to send me your database file I can create the MileSplit results file with the newest ART update and then send that results file back to you to submit to their website. If their website accepts it, then you know an update will solve the problem.