[tor-relays] DirPortFrontPage file '.....' not found | Permission denied

Hey, I'm having a little problem with setting up (my be some rights...) the html page on the relay DIRPort. On my logs :  00:00:03 [NOTICE] Tor 0.4.5.7 opening new log file.  00:00:03 [WARN] Could not open "/var/www/html/tor-relay.html": Permission denied  00:00:03 [WARN] DirPortFrontPage file '/var/www/html/tor-relay.html' not found. Continuing anyway. I've not found any information about how to set up this correctly. Many thanks in advance.