I have recently discovered that all of the settings URLs for all of the plugins point to the same plugin, MailChimp. For example, when I mouse over the Settings link of any of the plugins, the URL is shown as "wp-admin/options-general.php?page=mailchimpSF_options". When I deactivate the MailChimp plugin, the Settings link disappears for all of the plugins. I have tried reinstalling the MailChimp plugin but nothing changed.
I can't say what has changed though I did have to reinstall the User Access Manager plugin when an update failed. I had not checked the URLs before the reinstall so I can't say if they were working or not.
Any ideas or any more information I can provide to help?