Someone

Where is clamscan? [default is /usr/bin] /usr/local/bin
Setting ClamAV location in /opt/MailScanner/etc/virus.scanners.conf
You may need to add /usr/local/lib to the directories searched
for run-time libraries. Read the man pages for ld.so and/or ldd.
The symptom will be that the testing stage of the Mail::ClamAV
Perl module fails completely.