Ok, maybe that is a very silly question, but I have uploaded a guestook and when i run the setup file I get this message:

Parse error: parse error, unexpected T_STRING in /home/theories/public_html/Guestbook/config.php on line 29

Now, what have I done wrong? how can I change this?

I'd suggest you to check the file with a syntax highlighting editor (Homesite, Dreamweaver), probably an opening or closing bracket (or a single or double quote) is missing somewhere in your code.

Paul