Hi aihaike, I googled your error and came up with this:
http://www.redhat.com/archives/phil-.../msg00020.html
Ulrich Drepper is the main dev for glibc so when he actually has any advice to offer beesides "IT WORKS FOR ME", It's best to listen. That's still a fairly cryptic response but atleast he gave one instead of being a prick about it...
This is a really good link and you aught to read the first few paragraphs... Actually, you should REALLY read the entire page. Your annswer lies therein.. Notice the comment about U.D. It seems I'm not the only one who thinks he is an arse...
http://hr.uoregon.edu/davidrl/glibc.html
As the author implies, It wouldn't suprise me if tons of binaries break on your system after a sucessfull MAJOR # upgrade. I've taken to building my own distro these days and when I build a new glibc, I build ALL new packages against said glibc, especially if I use new kernel headers as well. Anyway, if you still want to press on, good luck...
Remember google, it's your friend when it comes to tracking down errors.