Hi
Lately these messages have been caused by systems which have a stable or testing version of libc, FWIU many packages in unstable are dependent on the unstable libc which has been held up.
thanks for the pointer, it is indeed libc6. Michel already pointed out that Braden's require sid, that would be another point to update in your doc christophe.
If you look at the details for the supporting packages, many require libc6 >= 2.2.5-13. Doing apt-cache show libc6 on woody reveals that the latest libc6 is below that requirement.
Jim