Help! PayPal Express Not Working!

I set up PayPal Express as a payment option for my cart but it gave me the following error on my failed order: Error: Order total is invalid. (Code: 10401, Severity: )

Has anyone heard of this before? Also, I was able to place the order using PayPal Express but when it brought my information back from PayPal, the first and last names were missing from the Billing section. Is this normal?

Thanks. Any help that can be offered would be great!