Wisdom means understanding. Attainment refers to the certification of attaining a particular fruition of enlightenment. This is the theory and practice of Bodhisattva vehicle. The Six Paramita being the Wisdom are practiced by Bodhisattva in order to attain enlightenment. However, this Sutra says that the wisdom does not exist, and there is no attainment at all. In fact, in emptiness, there is no wisdom and no attainment because the nature of all Dharma is ordinarily empty.
Thus there should not be any attachment to all Dharma. The ultimate enlightenment is the perfect wisdom, in which there is no attachment at all.