Constant Contact Add-On

The current unofficial Constant Contact Add-On has bugs, and the developer does not seem to be actively concerned about keeping that plugin up to date. I was wondering why Rocket Genius does not simply create their own official add-on for this?

Currently the main beef with the unofficial plugin is that it will not allow for registration to more than one list. At all. Not only can you not sign up for more than one list at once, but if you sign up for any list using the plugin, it is the only list you end up on - it removes you from all other lists if you happened to be on one already.

http://wordpress.org/support/plugin/gravity-forms-constant-contact
http://wordpress.org/support/topic/not-able-to-add-to-multiple-lists

+1 for an official Constant Contact Add On. I have the same issues that many others are having with Katz' Constant Contact add-on, specifically not being able to create a feed. It does not seem that this issue is high on Katz' list to resolve.

I was just able to resolve this issue via my host's support. I made a user account for them, and they said it was a matter of them programming a mod_rewrite/whitelist rule. When they made that happen, the plugin worked perfectly. Hopefully, that will help you as well.

Is there a step by step tutorial how to use the constant contact add-on?

During setup I get the following message: "Valid username and password. Now go configure form integration with Constant Contact!", which is hyperlinked and brings me to constant contact feeds page. I tried to create a feed, after selecting the form I create it, nothing happens.
Up top is this message "Warning: Creating default object from empty value in C:\xampp\htdocs\mysite\wp-content\plugins\gravity-forms-constant-contact\constantcontact.php on line 1146".

I uninstalled and reinstalled everything.

Any help is greatly appreciated.