Create service sample-webapp failed

Trying to learn how to put Docker containers on AWS EC2, I tried to launch the Amazon ECS sample.

All the options have been kept at their default value, except the Key-pair and the ECS Instance role, since they are needed. After having pushed the "Review and Launch" button, the container instances are launching, but the creation of the service fails:

Since the error message mentions the lack of load balancers, I started again and tried adding a port for the load balancing. The button "Review and Launch" was however disabled (gray and unclickable) when using the error balancing, making it impossible to complete the steps.

How can I make the sample-webapp work?

PS 1: I use the EU(Ireland) servers. PS 2: I have been given permissions to use ECS by another account, could it be that I have not been given all the required permissions? It's my current track...

Fail

-rights: I'm a second user