HTML5 and CSS3 validate 2 webs

i have 2 webs with same template based in HTML5, CSS3 and prestashop 1.5.3.1
I want to validate this 2 webs with w3c (http://validator.w3.org/) and put html5 and css3 logo in homepage

- www.tanburmusica.es
- www.barseg.cl

Also, I want to fix this apache warning an notice:

- mod_fcgid: stderr: PHP Warning: xcache_set(): XCache var cache was not initialized properly. Check php log for actual reason
- mod_fcgid: stderr: PHP Notice: Undefined index: HOOK_CATEGORY_FEATURE
- mod_fcgid: stderr: PHP Notice: Undefined index: HOOK_SLIDE_TAB
- mod_fcgid: stderr: PHP Notice: Trying to get property of non-object

Webs have same template, are based in prestashop 1.5.3
You can have root access to server if you need it.

Thanks