As is mentioned in our troubleshooting WordPress plugins
guide, you don't need to login to your WordPress admin in order to disable a problematic plugin.
For instance if you simply re-named your /wp-content/plugins/hellobar
directory over FTP or in the cPanel file manager to /wp-content/plugins/hellobar-old
this would disable that plugin from loading and hopefully allow you to access the admin interface again.
If you take a look at the WordPress The Hello Bar
plugin page, you'll see that it has a warning about the plugin being over 2 years old and no longer being maintained. So it's very possible that it has issues with a default WordPress install, or one using the Genesis framework
Please let us know if you have any further questions at all.