After updating my Mail Scanner and clam-av virus scanner, Clamav database was not updating. Then I found the error message in the mailscanner log
Error : Found generic installed
mailserver ClamAV-autoupdate[13274]: ClamAV updater clamav/bin/freshclam cannot be run
mailserver update.virus.scanners: Found generic installed
mailserver update.virus.scanners: Running autoupdate for generic
After removing the mirrors.dat I ran freshclam again, it starter working.
For my server
#locate mirrors.dat
/var/lib/clamav/mirrors.dat
#rm /var/lib/clamav/mirrors.dat
#freshclam
#update_virus_scanners
#update_virus_scanners