Dear Pierre-Alexis, the documentation on the ROS wiki  describes the common steps for various build configurations (the poky distro and the `nameless` OpenEmbedded-Core setup) and various release versions of ROS (hydro, indigo and kinetic).
At the release of meta-ros version 0.2 (for hydro), I tested it with the mainly-used build configurations at that time (OpenEmbedded-Core master branch and Poky dizzy). The current head of the meta-ros git repository provides indigo for the current master of OpenEmbedded-Core, and the Poky distro versions jethro and krogoth. Can you tell us which Build Configuration you currently use? (The build configuration is shown at the beginning of every bitbake run.) Which ROS distro version would you like to use? If you do not have hard constraints on the distro version, I suggest to go for the indigo release and use the HEAD from the current git repository. That version for meta-ros should work with the current master of OpenEmbedded-Core, and the poky distros jethro and krogoth. If you come across any further issues, please report them here. Best regards, Lukas