Yes and no. bbPress itself didn’t cause the issue. It was a conflict between bbPress and the OptimizePress theme. bbPress seems to work fine with the OptimizePress plugin. I found out that this was a known issue in that several people had reported it. Unfortunately, OptimizePress (the company) has done nothing about the issue even though it was first reported at least two years ago. I don’t think bbPress caused the login errors. I think those occurred because something got jacked up in the WP database after uninstalling bbPress. Luckily, I found out about force-upgrade.php which worked great to clean up that issue.
I wound up using Simple:Press for the forums. That plugin seems to work fine with the OptimizePress theme. You can see the page at http://yourpathtoweightloss.com/forums/. There’s not much to see, though. I’ve got two forums in there but I haven’t turned off the security for the forums themselves so they won’t be visible. I turned off the security for the page itself so people in the OptimizePress Facebook forum could see how the page was rendering. It’s not perfect but I’m going with it for now so I can move on to other things.