It seems that you're treating performance as a quantitative variable instead of a within-subject or repeated-measures factor. In other words, each subject has only one, not two, performance value. Your 3dRegAna script indicates that you're modeling the data with the following equation

Response = group_response + a1 * awareness + a2 * performance + a3 * awareness * performance + residuals

If a1, a2, and a3 are the effects of interest, your 3dRegAna script looks fine. However, if you're also interested in the group_response effect, you may need to center the awareness and performance values (usually around their respective mean) before plugging them into the model (and the script), and then construct the product of awareness * performance after the centering. That way the group_response effect can be conveniently interpreted as regard to the center values of awareness and performance.

Alternatively you can use 3dMEMA or 3dttest++ to run the analysis.

Gang