eM Client update breaks sending link from email to Firefox

I’ve updated to the latest version of eM Client (4.0.14479.0) and since doing that, if I click on a link to a website in an email, it won’t start Firefox (my web browser of choice) and it brings up a message that reads: “There was a problem sending a command to the program”.

Anyone having the same issue, and does anyone have any ideas? I’m using the latest build of Firefox (11.0).

Don’t know what happened, but this problem, which has been there since the update last week, has now suddenly vanished. No rebooting, no other updating, don’t know why. That’s worrying, but I suspect that the problem may not be easily reproducible for support or others, so I think we’ll regard it as “fixed” for the time being.