Mass Payments currency

When I try to submit the Mass Payment file to pay my Affiliate commission shares, I get this message from PayPal:

This Mass Payment cannot be processed because it exceeds your available balance. To raise your balance, you must add funds to your account from your bank account or convert funds from other holdings.

It is possible to subdivide your PayPal account balance into particular currency-based balances. To make Mass Payments in a currency different from your main PayPal account balance, you must first convert part of your main balance into another currency balance sufficient to cover the Mass Payment total in that other currency, then you can make the payments out of that currency balance. E.g., if your Mass Payments would be made in USD, and your PayPal balance is maintained in GBP, you must first convert a portion of your GBP funds into a USD balance sufficient to cover the payment total, then make your Mass Payments out of that USD balance. If you require further assistance to accomplish this, please consult PayPal help pages or support staff.