It should be okay as long as you are using a U.S. based credit card.
Why don't you download the software before you leave the U.S. so that you will not face that potential issue? Are you taking a laptop with you on the trip? Otherwise, you can use online TurboTax from anywhere that has internet access.
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**
