If you are not the student, of course you do not qualify. It's the student, the beneficiary of the 529 account, whose education expenses are qualified to be paid from the 529 account.
If the entire amount of the distribution is used for qualified education expenses of the student who is the beneficiary of the 529 account, the distribution is not taxable.
If TurboTax is treating the distribution as taxable, you have not properly indicated the qualified education expenses paid for the student, or you have not properly indicated the student associated with the distribution that you received. The key to getting TurboTax to treat the distribution appropriately is properly associating it in TurboTax with the student, regardless of the recipient, and making sure that the information pertaining to the student is entered properly.
Make sure that you are making all entries in step-by-step mode, not in forms mode. Make sure than any Forms 1098-T are also entered and follow-up questions answered. All forms need to be entered as received, with no modification.
[See Hal_Al's reply below regarding taking education tax credits instead of treating the 529 plan distribution as nontaxable. The tax credit will often reduce your taxes more than will reducing your taxable income.]
