There’s a little bug in 4.0.3 that appears (only) when production mode is set to testing or debug and you are using <txp:css n="nameofstyle" /> (or stylesheet links that look like css.php?n=nameofstyle). Pages referring in such a way to a stylesheet may appear unstyled and the stylesheet may return an error-message.
Easy Solution: Please set your production mode to live (which is always recommended for production sites anyhow) and you won’t experience the bug.
(Note: If for some reason you have the need to fix this bug in testing/debug mode as well, you can follow the instructions in this forum thread.)
