The solution is to enter "$1" as the beginning year loan balance and "$1" as the year-end loan balance. This won't have any effect on your tax calculations or your ability to efile.
From an economic perspective, it accurately reflects that you owed the same amount (virtually nothing) at both the beginning and the end of the year. It will, however, let the program know that you didn't forget to report at least some level of debt that would account for an interest expense deduction.
