browsers not liking php code widget

on this site i have the php below code in the 2nd left-hand widget (Products), which reports back the categories and how many items are in them.

<?php wp_list_categories('title_li=&child_of=4&show_count=1&exclude=90,5' ); ?> 

<?php wp_list_categories('title_li=&child_of=4&show_count=1&exclude=48,5' ); ?>

when you view it in Firefox or Safari everything looks great. But in IE and Chrome, you’ll notice everything is all out of whack. I’ve tried a number of different “PHP code widget execution” type plugins and all have the same problem. So I guess its not a problem with the plugin, but how the site is interpreting the php code in a sidebar widget??? FYI, I have the most recent wordpress version installed.

Please advise. Thanks in advance.