I have a problem when diplaying web pages which contain posts for a certain category, i.e. when category.php is used.
A blank line appears above a page layout (in Chrome and Firefox);
a blank line appears above the page layout and navigation menu is unorganized (in IE).
The problem doesn't appear when displaying a single post or a page (single.php; page.php).
The example page when category.php is used (error appears):
the example page for single post or page (no error):
An advice is very appreciated.