1. A fixed width layout of that size is too narrow for a 2 and sometimes 3 column layout. The site is crying out for a clean minimalist one colum layout. At the momemt is has too many lines dividing things up which is making it look fussy. That means a horizontal navigation bar.
2. I wouldn't put the ariticle links on the front page. The main purpose of the website is to flog wallpaper. I would concentrate on telling people what you have to offer and then providing very prominent links directing them to the important bits of the site i.e. the pages where they can select stuff to buy.
3. I know this seems like a strange thing for me to be saying but I would get rid of the forum. Helpful articles are a great idea, you will get peoples attention if you give them something useful for free. However, doing it by a forum is overkill. I suspect that even if the business is successful you will find the forum is harldly used. Its just not the right kind of product. Of course, you could hide most of the forum functionality so it looks just like an article publishing system which would give you a cms by the backdoor.
4. I'm also not too keen on the fadout background. It can make it look as if things have just fallen off the bottom of the layout. I think I might get a bit tricksy and give the bottom of the content area a torn paper edge which kind of fits in with the theme of the site.
Sorry if that seems critical, but you did ask.