syntax error breaking in and out of php into html code

I've just inherited some (pretty awful code) that I have to make some edits to, and came across a bit of a problem. A lot of the code breaks in and out of PHP and into HTML code: <?php while(condition) { ?> <li>some html here</li> <?php } ?> But when I check this my PHP parser is saying that this is a syntax error (checked in the browser and CLI). I know this is code from a working site, so it must be a setting within my PHP configuration. Now, I'm intending to re-write this anyway, as the logic is all over the place (SQL queries within the HTML, no separation of code and content, dozens of warnings all over the place) but I was wondering what setting causes this. It's mostly a curiosity thing really, as this thing is going to be re-written faster than an school project the eve before hand-in. -- Thanks, Ash http://www.ashleysheridan.co.uk