How do we use *Merge Launchpad accounts* ?

Maybe it's because I'am tired those days, or not fluent enought in English to get a tricky point or stupid me.

But I fail to use the *Merge Launchpad accounts*.

 To merge two Launchpad accounts:

    * You must be logged in to Launchpad under the account you want to keep.
       => I am logged on Samuel Buffet the account I want to keep.
    * You must have access to the e-mail address registered under the duplicated account.
      => I've access to that email

Below Duplicated Account (Required), I search the old account I want to merge with my new one.

I found it. (human enemy)
I click on the it.

I click submit and ...

=> I've the message

"
Not allowed here

Sorry, you don't have permission to access this page.

You are logged in as Samuel Buffet."

and no mail ?

What am I doing wrong ?

Thanx :)