Notice that the URL it's putting up there has nothing to do with TalkBass. You likely do have a virus (malware) and it's creating that screen so that you'll panic. Or the malware is directing you to another URL behind the scenes and that is being flagged. I don't think it's a problem with TB; it's more likely a problem with your computer.
I'm on a Mac, so very few viruses, and I don't see one here, but if you have a way to run a legitimate virus scan, I would run that and see what happens.