Jeff,
I fear that a lot of your addons will not be supported any more. For instance, Members Map doesn't exist, and it was (I believe) rewritten and called Community Map. However, @Martin A. did or does have an upgrade option to import all your old markers.
As for your other plugins/addons, you'll need to go through them and see if they're able to be upgraded and whether you need them. And yes, an old theme can cause problems. Ideally, you'd need to disable all addons/plugins and run the default theme and update the site that way, ensuring that ALL NEW FILES overwrite the old ones on the server.
I don't mean to be another just to jump in and confuse issues, but it's best that you restore your forum and keep it as is until you're 100% ready to upgrade.