It appears that when I try to use a child theme along with Picolight I get unexpected results in any Windows OS (XP, Vista, 7) using IE 7 or 8. IE 9 is fine.
I have two client sites using a child theme & Picolight; one crashes before it loads: http://www.homewinemakersclassic.org
The other crashes when a navigation link is clicked. I am working on this one so the link won't help I have not noticed problems in any other browsers.
I went as far as to test this just loading the Picolight theme from the child CSS like so (XXX in place of personal info):
Theme Name: Picolight Child 2
Description: Child theme for the Picolight theme
Author URI: http://XXXXXXX.com
I added no other CSS. This crashed as well.