Anonymous users randomly get 404 errors on front page I have a drupal 6 site that will occasionally serve up a 404 error to anonymous users on the home page only.  It happens 2 or 3 times a day and I cannot figure out what is causing it.  I can clear it by logging in and flushing the cache, or going to site information and re-saving that form.

We are using the mobile tools module which I thought might be conflicting somehow, but I can't find any issues in the issue queue related to this.  We are using caching, but it's just standard drupal caching.  

I've also tried checking the server logs and watchdog and I can't find anything useful.  Does anyone have any ideas?
It looks like it was due to a permissions issue.  I set all files and folders to the correct permissions and it seem to fix the issue.

I also updated to the latest dev version of the mobile tools module.