Dreaming of dunes can have a lot of different meanings. For example, dunes are basically little divots in the sand. There is a large expanse of sand and every little microscopic drop in that large expanse of sand makes up one of many dunes. Of course these are not actually microscopic drops but it seems like it in the larger scheme of things when it comes to driving through dunes. If you have a dream of dunes then this means that you are worried about all of the little speed bumps that life has to offer. Basically, dunes are just potholes of the desert because they appear in the sand and can ruin a vehicle if it appears at the right (or in this case, wrong) time. If you are dropping into a lot of these dunes and falling short of your goal then this dream means that you are going to have some issues finding success in life. You are falling short of where you want to be and it is making you frustrated, but you are not sure what you are supposed to do about it or even how you should go about fixing it.
On the other hand if you have a dream about dunes and you are in a dune buggy or have a camel and are effortlessly navigating all of the pitfalls and issues that exist in the desert then this means that you have done a good job and that you have prepared yourself well to get through whatever strange or complicated issues that life may throw at you now or in the future.