My friends and I have the exact same problem so I assume this was caused by the last update.
Same here happened after the update on 7/24/2015. After login to my multiplayer ME3 lobby I could not go to my invite friends list, instead
a screen popped up telling me (You must "enable Origin in Game" on Origin (EA) client's setting page to use this feature.)
There was another EA update this morning 7/25/2015 but no change the message still appears when I go to my multiplayer
lobby and try to invite friends. First of all, where is the "client's setting page" located in Origin or EA? I can't find it....
I'm having the same problem, but I don't get any error messages. When I press shift-F1, nothing happens at all. But I think this is what's being referred to: If you go to the main Origin menu and select "Origin", then "Application Settings", that will take you to a page labeled "Settings" which has 5 tabs down the left side. The fourth is "Origin In Game". Select that tab and you'll see the option, "Enable Origin in Game".
However, this doesn't help, at least not in my case anyway. When I first found this option, it was not even selectable. After closing and restarting Origin a couple times, it became selectable once. I then changed it, with no effect. Then I changed it back. Again, there was no effect. And now, it's become unselectable again.
According to the settings on this page, "Origin In Game" is enabled. But I can't access it. But I still get the pop-up notices when friends log in and out.
Also, I've tried uninstalling and reinstalling Origin. That was useless, and I'm out of ideas.
