Glad we've determined there is nothing ClamAV found on the server, but ....
am not sure if what you are doing/thinking is correct nor safe.
IF you are relying on ClamAV on the Moodle server to protect it from accepting files containing a virus and thus protecting workstations by proxy, you should know that ALL antivirus apps are NOT 100% and that new viruses/malicious software, etc. is continual and on going. AV is only as good as it's AV definitions and engine to ID such files correctly.
Get your techs to check out the Macafee on workstations is up to date and functioning.
Turning it off on a Windows PC is not something I'd advise.
Best of luck!
'spirit of sharing', Ken