permission denied with cap deploy from another machine

Hi,

I am trying to deploy a Rails app from another machine than I did before
and get permission denied errors. Everything the app needs is on the
same root server.

config/deploy.rb

------8<---------------------------
set :git_enable_submodules, 1
set :application, 'kunsthof'
set :repository, 'user@myserver.tld:/home/user/git/app.git'
set :scm, :git
set :use_sudo, false

if ENV['DEPLOY'] == 'PRODUCTION'
  set :deploy_to, '/srv/www/app'
else
  set :deploy_to, '/srv/www/app_staging'
end

server 'myserver.tld', :app, :web, :db, :primary => true
------8<---------------------------

Following the server's logfile I get the permission denied when
capistrano tries to log in from the server into the repository on that
same server via ssh (by using a password).
As I said, I don't get that error deploying from my original development
machine.

How is that possible? Whats the difference?

Another question is, if it is possible to say capistrano that it is
pathetic to log in on the same machine via ssh when it just could take
the repo from it's path.