Mark a post as unread [Deleted]

I'm excited about using this add-on, it will solve a lot of problems for us. But when I try to install it, getting this message:

Callback phc_MarkAPostAsUnread_Listener_Listener::load_class_controller is invalid (Invalid Class).

I'm running 1.5.3 ...
You have not uploaded all the files correctly
You were correct, I had not. Thank you, now it's installed and working! Thank you!!

However, now see what I did not understand before:

This add-on marks a post as "New" for everyone on the forum - I had imagined it just marks a post as 'unread' for yourself. That is what I really need.

Is there a way to modify this so I can just mark posts 'unread' for my own user - and not anyone else's?

Thank you for this nice addon! Works fine and is highly appreciated!
Is there any chance to get the posts marked as unread only for the current user - not for ALL users?
Does anyone have a working version of this addon, or can point me in the direction of something that does the same thing?
I don't know exactly what you need this for and this solution might not work for you, but I installed this add on:

We had RSS feeds coming in our staff section and wanted to move them to the public forum, but when we did, they didn't show up as new for anyone who had marked forums read after the date and time that the thread was originally generated. When we moved them to the public forums, nobody knew they were new threads. Now if we change the date and time to the current date and time when we move them, they show as new. I'm not sure if will work for your needs, but it's the only thing we found. Good luck!