Curse-of-ghost
This I believe has to do with ghost fence. This curse is caused by the tribunal trying to maintain the blight within red mountain. this is a curse because the dunmer have to sacrifice part of the soul of the dead who the dumer worship. It has been stated that a great many souls were sacrificed to maintain the great ghost fence.this is stated in "ancestors and the dunmer" "With the vast majority of ancestors' remains going to strengthen the Great Ghostfence around the mountain of Dagoth Ur"
curse-of-seed
This curse is more obsure. but I believe that it has something to do with nothing can grow around the blight. I'm not quite sure. but seed is also mentioned in another prophecy called "The lost prophecy". They could have something to do with each other.
curse-of-despair
I believe that this curse has to do with the ppl begining to doubt their gods. The reason for this is from the document dagoth ur's plans when it states "The inner circle of the Temple priesthood has begun to suspect the Tribunes have suffered seriously from wounds and demoralization in the wake of reverses at Red Mountain, but do not recognize the scale of the problem."
Refecences that I used
Dagoth ur's plans
The lost prophecy
The seven curses
Ancestors and the dunmer