what could it be a reason for such an error:

If I go: http://myhost/munin/

I get 403 Error: Forbidden. You don't have permission to access /munin/ on this server.

Permissions for files are the following:

max@ubuntu:/var/www$ ls -l

total 8

-rw-r--r-- 1 www-data www-data  180 2011-12-28 16:06 index.html

drwxr-xr-x 3 www-data www-data 4096 2011-12-28 08:55 munin

ADDITIONAL:

Thank you very much for your help! I did fix it by deleting the dir and targeting munin output html to another dir (actually with the same permissions). I use that apache only for munin, so that strange behavior is ignored.

I did try to access that my numin stats via DNS name. All files in the same www dir were available, also all files in sub/sub/sub/dirs were also available. Only ../munin dir was not working as I expected for some unidentified reason.