The moodle home page and the moodle courses pages are built using a table. The first and the third column of the table have the width taken from an hard coded style: <td style="width: 210px;" id="left-column"> and <td style="width: 210px;" id="right-column"> that is not permitted by the "Requirement No 2 point 1" of accessibilityin http://www.pubbliaccesso.gov.it/normative/DM080705-A-en.htm.
(avoid using, within the markup language in which the page is coded, elements and attributes to define the page's presentation characteristics (for example, characteristics of the text characters, colours of the text and the background, etc.), and use CSS (Cascading Style Sheets) to achieve the same graphic effect instead
There are also some other hard coded style call that shoud be removed.
Into my moodle 1.8+ installation in http://www.eduiss.it I also have:
<div id="overDiv" style="position: absolute; visibility: hidden; z-index:1000;">
in the calendar
<div id="noscriptchooselang" style="display: inline;">
for the language script free go button