How to fix update hiccups easily:
Go to clamav.net, download the Win64 file (that's if your system is running a 64bit processor) under "Alternate Versions of ClamAV" The file should be called something like: "clamav-0.102.4-win-x64-portable.zip" Before you extract this into the immunet folder, you need to stop the service under windows, hit the "start" button, in the run box type: "services.msc" (this shows you a panel with all your services) locate the entry: "Immunet 7.3.0" double click it, when the dialog shows up, click "Stop" it should take a few seconds to stop the service (if it doesn't stop the service, run services.msc as admin by right-clicking services.msc as it comes up in the results and choose "run as administrator" the icon will look like 2 silver cogs and say "services" in the search results)
So once you stop "immunet 7.3.0" service, you can now extract your ClamAV zip file, right-click, extract files....., choose location: C:\Program Files\Immunet\clamav\0.102.1.76 (your version might differ, but extract it in the folder following clamav under your version number, when you extract the files it will ask if you want to "overwrite" existing files, click "yes to all".
Once extracted you want to locate "Freshclam.exe" or just "freshclam" double click or right-click and run as admin (if you like) it will take a bit, but once you've updated your clamav, you can go back to services.msc and start "Immunet 7.3.0" by clicking the "start" button in the dialog panel.
You can now update your Immunet software via the "update now" button.
Hope this helps