You can sue anyone for anything, but unless the computer system is certified by the FDA as a "Medical Device" then you're unlikely to win a judgment. It would be like suing the publisher of a diagnosis textbook that contained incorrect information. That's the reason that clinical decision support vendors typically design their systems to just show possibilities rather than explicitly making a diagnostic recommendation. It's ultimately still up to the doctor and so the doctor bears all of the legal responsibility.

Yes, but the comment I was replying to was within the context of all doctors being replaced by computers, and his point was that it couldn't happen because there needs to be a person to blame. Well, if you get rid of the people (except those creating the computers), then it is still possible to sue the computer owner and/or creator.