Need help defining IE specific stylesheet with Zen Starter-kit and Conditional Stylesheet Module
If this link is in your head it is like if the css file is in a folder under the currrent one. You need a first backslash: &lt;!--[if IE]&gt;&lt;link rel="stylesheet" type="text/css" href="/sites/all/themes/THEMENAME/css/ie.css" /&gt;&lt;![endif]--&gt;

As you can see in the answer you linked the definition in .info file has to look like

stylesheets-conditional[IE][all][] = css/ie.css


not

stylesheets-conditional[if IE][all][] = css/ie.css


(I just have it from this answer - never used this module). Honestly I would not install a module just to add conditional comments for IE. It is easier and saves performance eating module to put them simply into the html.tpl.php - you just have to keep the right paths.

stylesheets-conditional[!IE][all][] = css/ie.css


Makes absolutely no sence - I do not know if this module could interprete that. But at least no browser in the world would read a css file in such a conditional comment: every browser except IE ignores conditional comments. So you tell the only browser who reads them that this file is notfor it to use... you got it :)