Notice: nested emphasis ...

Cause:

The same tag is containing himself. The second tag add no more information.
This is not a HTML error.

Solution:

Remove one of the tags

Sample:

nested emphasis <b>
BAD       <b><b>This is bold</b></b>
GOOD    <b>This is bold</b>

References:

HTML specification: http://www.w3.org/TR/html4/