In the Douay-Rheims this verse reads: "For our wrestling is not against flesh and blood; but against principalities and power, against the rulers of the world of this darkness, against the spirits of wickedness in the high places."

However in most other translations I've checked, "high places" is translated as "heavenly places". Is this what the Douay-Rheims means by high places? If so, what "spirits of wickedness in heavenly places" is it referring to? The Orthodox sometimes use this verse as proof for Aerial Toll-houses, and I'm not sure how to address their claims. 

Why concern yourself with other translations that aren't Catholic?

Those same books have Genesis 3:15 translated differently, too. Why consider heterodoxy that is premised off of erred translations. Stick with the Catholic bible.

I am sticking with the Catholic Bible, hence why I asked what it means when it refers to "high places". I just brought up the other translations to ask if that's what it meant. 

The Haydock commentary does not explicitly address the expression "in high places" but might be of use anyways:

Flesh and blood, which may either signify temptations of the flesh, or raised by mortal men. — Principalities and powers; i.e. devils, or apostate angels, who before their fall were in such ranks of spirits, and who are permitted to rule over the wicked in this world of darkness. Wi. — By which we are to understand the fallen angels. For as by nature, and from their creation, they were the governors of this corporeal world, and were deprived of this their power on account of their pride, they received it (though limited by certain restrictions) in order to tempt man. Estius. — Rulers of the world of this darkness. By these are meant the devils who exercise their power and authority in our inferior and dark atmosphere, by raising winds, storms, tempests, &c. By darkness may be understood the wicked, in whom Satan reigns as in a citadel. Menochius. — Our inferior world is called dark and misty in comparison of the world above, which is always bright, serene, and clear. Our atmosphere is called the cloudy and dark heavenly.

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St. Thomas's commentary does address the usage of the expression exclicitly, although the Angelic Doctor himself is a little unsure of what the preferred meaning should be:
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He mentions in the high places for two possible reasons. Either to show the strength and advantage they possess to overcome us; we are on the earth, but they are on high in the dusky atmosphere so that they have the better position. “And the fowls of the air devoured it” (Lk. 8:5). Or, he says in the high places because this struggle is for heaven, and this should urge us on to fight.

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