VPOP3 Antivirus update error 50

>I've been getting these error messages. Please advise what the issue is and how to resolve it.
> VPOP3 has been unable to successfully download an antivirus update in the last 399 minutes. It has tried 200 times
> within that time. The last error received was:
> The VPOP3 Antivirus Update attempt failed with error 50

In the VPOP3\plugins\VPOP3AV folder, can you look in VPOP3AV.CONF and VPOP3AVU.CONF

Do they both have lines saying:

DatabaseDirectory .\db
If not, add them and see if that fixes the problem