I'm terrified of hieghts too, just for an example I was in the Sears Tower in Chicago, once and my body wouldn't let me walk within 15ft. of the glass.

The first couple of years I hunted; I had an old API hang-on stand that was less than stable. I could barely force myself on to it and forget standing on it. The tree stand wasn't the problem, its was only part of the problem. I eventually got a nice stable API Bowhunter and that up'd my confidence a lot. Then (I know you said not to mention it) I got a real nice harness that is integrated into a vest; that was a big help. I am still extremly scared of heights, but it seems that the more time I spend in my stand the better I can tolerate it. When I first started hunting I couldn't set my own stand because I couldn't let go of the tree long enough to hang it, but keep taking little steps and eventually you'll get somewhat used to it.

The other thing that helped, and I know this sounds stupid but... We have a guy in our group that is even a bigger pansie about heights that I am. He can't even get half way up the ladder on his ladder stand on a good day. I just told myself "you don't want to end up like that guy," and forced myself to less scared of heights than he was.