Problems with git (staging)

[Marc Hohl]

Hello list,

I tried to follow the instructions on
http://lilypond.org/doc/v2.15/Documentation/contributor/working-with-remote-branches

Since I have now push access and I am supposed to push to staging,
I tried to create a local branch called 'staging' and I did

git config --add remote.origin.fetch 
+refs/heads/staging:refs/remotes/origin/staging

git checkout --track -bstaging  origin/staging

The first command showed no output, the second one complains with

fatal: git checkout: updating paths is incompatible with switching branches.
Did you intend to checkout 'origin/staging' which can not be resolved as commit?

Do I misunderstand the CG or am I missing something else?

Marc