Paroketh is not strictly part of the Tree of Life. Rather, it is a state or entity that one may encounter while journeying on the Tree.
The origin of the word Paroketh is obscure: it is not Biblical, nor modern Hebrew. Strong's Dictionary gives it as a Hebrew word with the meaning of veil or curtain, but without citation. The Biblical Hebrew word for a veil is Vilon (וילון), while in the Exodus description of the Temple the curtains are referred to as Yeriah (יריעה), tent sheets. There has been a suggestion that Paroketh derives from the Greek, but this too is unsatisfactory. In the New Testament the Greek word used for the Veil of the Temple is Katapetasma (καταπετασμα) or Kalimma (καλυμμα). The jury remains out.
Paroketh resides on the Tree of Life, between the level of Hod and Netzakh and that of Tifaret. It is known as the veil of illusion.
According to the Buddhist worldview, the physical Universe that we occupy is an illusion. This is true, in the sense that every thing, every entity we see around us has existence only insofar as we have given it a name. In reality, there is only energy, and flows and concentrations of energy that give the appearance of solid matter.
From this point of view, we can pass from the world of illusion through the veil of illusion into the world of spiritual reality. But the world of the spirit as we see it is an illusion too: the reality is certain enough, but our minds can only comprehend it in terms of our own mental capacity, which is necessarily limited because it is finite. This is why we comprehend our incursions into the spirit world in terms of encounters with angels and demons, or journeys through the heavens in fiery chariots. The spiritual Universe contains angels and demons only because we have labelled certain energy constructs in this manner. In just the same way, the physical Universe only contains the concept of "table" or "floor" because we happen to perceive certain energy constructs in a particular way.
So from this point of view, the veil of illusion conceals from our everyday senses a greater illusion beyond. But the veil of Paroketh is itself illusory, because there is no real division between the physical and the spiritual worlds. We may pass between one and the other as easily as passing through a hanging curtain. Of course, first one needs to know how to move the curtain aside; but this is something that has been given to us by many avatars in the past. At Christ's crucifixion, it is said, "And the veil of the Temple was rent from the top to the bottom". This means that Christ, in his teachings, gave us the means to see through to the other side of the veil by our own efforts; no longer do we need the intercession of a priest before we are able to approach God's kingdom.
So is there no veil of Paroketh, no obstacle to our progress at this point on the Tree of Life? Yes, there is, but the obstacle is of our own making. Part of the problem is the Tower path, where our own particular belief system, and particularly the attempt to express our own particular belief system in any kind of human language, may lock us into a pattern of perception where we are unable to transcend the veil and see clearly what lies beyond it.
But a deeper problem is that our expectations of what we will find beyond the veil are so clear and well defined that we may build up a mental image of it that is so strong that we can convince ourselves that we have been there, when in fact we have not.
So should we dismiss all images and expectations of what we will find when we approach the world of Tifaret? Ideally, yes, but this is not a practical way of working for most thinking, feeling, human beings. Instead we try to develop the image through familiarisation, repeated travel on the paths approaching Tifaret, while recognising that this is a journey of the imagination only. Then suddenly, one day, a certain flash of enlightenment will come to us; we will realise that we are actually in Tifaret, and the veil of illusion will finally drop away, and drop away forever.