I just did a fresh install of Nagios 3. When I go to the website, it always fusses at me saying that it cannot read from the status log file. Once I refresh the page though, it pulls up the correct information. I double-checked my nagios.cfg file to ensure that the file is configured correctly and the location path is right. I also checked the permissions, all users have rw permissions on it.
On a related note, NagVis can access the information from my MySQL database correctly, but the link to the host page still shows the error until I refresh.