An answer to what exactly ? The edits cannot have the effect mentioned, there is no other answer.

For some reason it doesn't send out the mails.

They stay in the E-Mail Queue.

Can anyone confirm that this mod does work with 4.0.3?

Yes. It works on 4.0.3, and any other 4.0.x version.

Strange, because it puts the emails in the Queue but it doesn't send them.

It works if I run the task manually.

Then you have an issue with your cron jobs running.

Thanks :)

How can I do it?

Thanks installed :)

This doe snot seem to work in 4.0.7. I turned off the task to Process the Email Queue, and emails are being sent out in less than 1 minute.

It seems like 4.0.7 is ignoring this product.

Some e-mails (like registration e-mails) are never queued.

However, the more likely answer is you didnt re-do the file edits after you upgraded to 4.0.7.