If you happen to maintain your webpage with Drupal and also host a SVN-Repository on the very same host you can run into trouble. Just try to commit a file starting with a period (for example a project file from eclipse: .project). It will give you an error "access denied for unknown reason". The solution is quite simple. There is a rule in the .htaccess file from Drupal which denies access to files starting with a period. You can either delete this rule or restrict it to only apply for the drupal part of the page.