Error:
===============
[root@localhost ~]# /etc/rc.d/init.d/clamd start
Starting Clam AntiVirus Daemon: LibClamAV Error: cli_loaddbdir(): Can’t open directory /var/clamav
ERROR: Unable to open file or directory
[FAILED]
===============

This is caused by an enforcing SELinux policy

Disable selinux using setenforce=0