I think your file is incomplete. There are a few columns that are required:
You have to select 1 in either Selling or Buying
Then in Applicable for Column you have the options:
Customer: Customer, Customer Group, Territory, Sales Partner, Campaign
Then depending on what you selected, you have to select an appropriate value for Customer, Customer Group, Territory, Sales Partner or Campaign.
Try again with this. Plus as a rule always download all columns in the data template.
Hope this helps.