A slightly sinister way to encourage posts would be to pay a college student to reply to everyones posts quickly under several names. A forum that seems full of knowledgeable people will attract more interest than a seemingly stagnant one. Another way (slightly less underhanded) would be to reply to as many posts as you humanly can. Again, a busy forum will encourage more posts.
you need time to let the others to kowe your forum. another side the most important of a forum is the contents and topic,if it is intereste,your forum will not be difficult to increase posts.
The forum certainly has a lot of potential; the layout is great, and you obviously want it to do well. But there are a few obvious things that may be controbuting to your lack of posts. Firstly, your forum idea is very specialised. From what i can see, nearly all of the topics are geared towards a certain theme, with little rom for expansion into other topics and ideas. This isn't really something you can change, but it may be a reason for the lack of posts.
Another thing is that you have way to many topics for users to post in, with many of them empty of posts. The forum is absolutely massive (in terms of forum topics) compared to the number of users. My suggestion would be to delete a few, perhaps merge a couple together, and then create new topics when users call for them. Having less topics will also give the forum a much better look and feel; it will shorten it, and make it look nicer, and having more posts in less topics will make it feel nicer. A friend of mine once said '10 posts in five topics looks better than five posts in 10 topics'.
Hope this helps.
if your site Contains Download Links, I suggest you install a HIDE HAC system so that when someone posts a link the members will ahve to post a reply inorder to see that link.
Alternatively you an offer prizes for a certain amount of pots,etc. This way your users have a motivated way to post, instead of just being leechers who live off the hard work of others.