Is there a How-To guide (or something of the likes) that tells me how to create and individual archive with full commenting support? For the longest time I have used pop-up commenting support but is there a way to have it in the same page as the individual archive entry? Any help is greatly appreciated.

The default templates have comments forms on the individual archive pages. It might help you to take a look at this template and adapt it for use in your own template. Basically, you will need to add a lot of javascript code in the head section of your template and then the comments listing and submission form in the body.

I've gotten the individual archives working just fine, but how do I set up the page to display the preview and also display any error messages?

Your individual entry archive page is a static webpage, like any other. In order for the comment to be processed, it has to be submitted to the mt-comments.cgi script. The preview and error templates are part of the processing of the comment, and have to be dynamically generated by the CGI. To the best of my knowledge, it's not possible for them to function within the individual entry page.

When you submit a comment from your individual entry page and it goes to the preview or error page, that will open in the same browser window. Once the comment processing is complete, you will be taken back to the individual entry page, where the new comment will be displayed in the listing.

Is that a problem?

Yes it is. I use alot of dynamic PHP code that will not work in Perl. It will case the style not to be show, aswell as the side menus to dissapear on the site. Is there a way to have the error message appear in a pop-up window when something wrong has occured?