Category Problems…. tutut

You’ll want to look at Category Templates as well as get a feel for the Template Hierarchy.

At this moment a link would be beneficial.
Seemingly, your issue is related to the setting of how many posts to be shown (admin > Options > Reading). The settings from there apply to ALL views in your blog.
However, there are plugins (CQS=custom query string) that would allow to have different number of posts on different views.

My guess was correct!
Go to your Wp admin panel > Options > Reading.
The “Show at most” field must be set to 1 (one).
As I said above: that setting applies to ALL your pages/views.

Search for the plugin I mentioned above.

It’s not your CSS – it’s your archive.php or category.php, whichever is used to display your category listings. It has a lot of bad code in the header (head), the validator doesn’t even want to work with it 🙂

I just checked the source for one of your category pages. Look for this:

<a href="/Brushes" title="Brushes"><img class="no" src="wp-content/themes/Illustration/psp.jpg" alt="Looking for Paint Shop Pro Brushes?" title="Looking for Paint Shop Pro Brushes?"</a>

You have an img tag that isn’t closed. Perhaps closing that will fix your problem?

The failed validation:
http://validator.w3.org/check?verbose=1&uri=http%3A%2F%2Ftwisted-barfly.co.uk%2F%3Fcat%3D4

and when forcing the validator to show the code (and source):
http://validator.w3.org/check?uri=http%3A%2F%2Ftwisted-barfly.co.uk%2F%3Fcat%3D4&charset=iso-8859-1&doctype=Inline&ss=1&group=0&verbose=1