My son had something similar happen (I think he was a little older, though).
He would wake up at the same time every night, at the same time, yelling. When I went in to help him he would be really angry and would push me away or yell at me, and he would never tell me what his dream was about (I couldn't tell if it was because he didn't want to, he didn't really remember, or it was too bizarre to describe (I think it was this last one)).
It was awful for me, but he was no worse for the wear - in other words he eventually out grew it with no ill effects. In fact I hadn't thought about this for quite a while now.
I don't think these were truly night terrors, just vivid dreams that were scary - either in a real sense or because they were so weird.
I thought the past life comment was very interesting, I never thought of that, since my son is very intuitive (an "old soul" as they say), I suppose it's possible.
In any case I'm not sure there is much you can do, but it should pass in time. Good luck!