Welcome to MSN! Unfortunately this problem you are encountering has been happening for months. Has MSN been able to figure it out? No. Makes you wonder who is programming and fixing these errrors - whoever it is....I'm not impressed.
I still can't upload my .CSV files. It complains that file must be .XLS or .CSV, etc..... I even tried uploading their example .CSV file and that didn't work. I'm pretty sure my files are compliant. I've uploaded with same format many months ago.