You say the error is:
/usr/bin/tail: cannot open `/var/log/httpd/access_log' for reading: Permission denied
By default, the permissions for /var/log/httpd/ is that only root may read and write to that directory. Logging is handled by the parent httpd process, which runs as root. Children of this process run as user 'apache', and they cannot access the directory:
user@host:~ $ ls -ld /var/log/httpd/
drwx------. 2 root root 4096 Feb 11 11:44 /var/log/httpd/
One short term fix is to change the permissions of
user@host:~ $ sudo chgrp apache /var/log/httpd/
user@host:~ $ sudo chmod g+rx /var/log/httpd/
user@host:~ $ sudo ls -la /var/log/httpd/
drwxr-x---. 2 root apache 4096 Feb 11 11:44 .
drwxr-xr-x. 9 root root 4096 Feb 18 02:36 ..
-rw-r--r--. 1 root root 0 Feb 11 11:44 access_log
-rw-r--r--. 1 root root 596654 Feb 7 12:04 access_log-20130211
-rw-r--r--. 1 root root 693 Feb 18 02:36 error_log
-rw-r--r--. 1 root root 11531 Feb 11 11:44 error_log-20130211
However, use caution with this. The designers of Apache chose to make
/var/log/httpd/ not-readable to user Apache, probably for security reasons. Right now I cannot remember why they chose this design, but perhaps someone else could chime in.
Also see Stackoverflow: Apache access log automatically set permissions