From OSSEC Wiki

OSSEC-WUI Permission Denied Errors Due to SELinux on Fedora / Redhat Based Systems

See this mailinglist post for more context: mailinglist post

For this example, the web dir is /var/www, and ossec is in /var/ossec:

chcon -R --reference /var/www/ /var/ossec/

That is what worked on my FC6 box. And it worked on F7 (just confirmed).