Inline PHP for WordPress 2.8.6 (Conditional)

WORDPRESS VERSION: 2.8.6 (I just did an upgrade from 2.7. everything was working GREAT with 2.7!!)

INLINE PHP TO RUN (pasted on the first line of EVERY article):
< ?php if (is_single()) { ?>
< ?php include (TEMPLATEPATH . ‘/ads-single-top.php’); ?>
< ?php } ?>
(which basically is a conditional php code that includes adsense ONLY when viewing the article in single.php)

The php works great when viewing the article in single.php.. but once it comes to index.php.. it doesnt work. On index.hph I am using “<?php the_excerpt() ?>”

I tried searching for plugins that RUN PHP INLINE code.. and they work.. but only on single.php (like I said before)