Fundamentally, if you are unable to run your own files on your own computer, then you will be unable to run files. At some point the antivirus software is only making things worse for you.

If you really can't control the program that prevents you from running your own files on your own computer, and you already have an earlier version of JJ2+ (or can acquire one using GOG), you can download plus.zip and extract a new plus.dll and plus.j2a manually. But if your antivirus then randomly decides it doesn't like plus.dll, for example, then you will be unable to play JJ2+ no matter the installation method.