What version of ansible (ansible --version) ?
Also can you show me where you set those variables?
Actually it was the developpement version, but the last time I tried, it was on a fresh git clone 15h ago.
As I use ansible in production I had to rollback to the 0.7 version
This is my playbook :
Oh, so basically it looks like you want to use vars from the first
vars_files in repeated vars_files.
I suspect that doesn't work now but it is a good suggestion and we can
make this work.
as a workaround, putting defaults in
/directory/where/your/inventory/file/is/group_vars/all
Group variables get loaded first and 'all' is a magic group that all
systems are in.
Will look into the underlying vars_files usage as this should be
rather easy to fix.
Thanks!
in 0.7 version its does work very well 
2012/10/2 Michael DeHaan <michael.dehaan@gmail.com>