dapper can't build itself: klibc build depends failed

on an up-to-date dapper
using an up-to-date pbuilder
the build of klibc fails, because build depends can't be met.
Log attached.

...............................................................

$ apt-get source klibc --download-only
Reading package lists...
Building dependency tree...
Need to get 572kB of source archives.
Get:1 http://megaera dapper/main klibc 1.1.16-1ubuntu5 (dsc) [1390B]
Get:2 http://megaera dapper/main klibc 1.1.16-1ubuntu5 (tar) [554kB]
Get:3 http://megaera dapper/main klibc 1.1.16-1ubuntu5 (diff) [16.1kB]
Fetched 572kB in 0s (4943kB/s)
Download complete and in download only mode

$ ls -l /tmp/pbuilder-wrapper-1175197564-679
total 568
-rw-r--r-- 1 buildd buildd 16074 2006-03-12 19:06 klibc_1.1.16-1ubuntu5.diff.gz
-rw-r--r-- 1 buildd buildd 1390 2006-03-12 19:06 klibc_1.1.16-1ubuntu5.dsc
-rw-r--r-- 1 buildd buildd 554329 2006-01-17 06:10 klibc_1.1.16.orig.tar.gz

$ sudo /usr/sbin/pbuilder build /tmp/pbuilder-wrapper-1175197564-679/klibc_1.1.16-1ubuntu5.dsc
W: /home/buildd/.pbuilderrc does not exist
I: using fakeroot in build.
pbuilder-buildpackage/i386 $Id: pbuilder-buildpackage-funcs,v 1.28 2005/12/21 11:57:29 dancer Exp $
$Id: pbuilder-buildpackage,v 1.120 2006/01/06 12:30:51 dancer Exp $

Current time: Fri Mar 30 05:46:04 EST 2007
pbuilder-time-stamp: 1175197564
Building the build Environment
 -> extracting base tarball [/home/buildd/the-pbuilder-way/base.tgz]
 -> creating local configuration
 -> copying local configuration
 -> mounting /proc filesystem
ln: creating symbolic link `/home/buildd/the-pbuilder-way/build//20410/etc/mtab' to `../proc/mounts': File exists
 -> mounting /dev/pts filesystem
 -> policy-rc.d already exists
 -> created buildresult dir :/home/buildd/the-pbuilder-way/result/
Installing the build-deps
 -> Attempting to parse the build-deps : pbuilder-satisfydepends,v 1.22 2005/12/04 05:16:40 dancer Exp $
 -> Considering cdbs
   -> Trying cdbs
 -> Considering debhelper (>= 5.0.0)
   -> Trying debhelper
 -> Considering linux-headers-2.6.15-18
   -> Trying linux-headers-2.6.15-18
       -> Cannot install linux-headers-2.6.15-18; apt errors follow:
Reading package lists...
Building dependency tree...
E: Couldn't find package linux-headers-2.6.15-18
W: Unable to locate package linux-headers-2.6.15-18
E: Could not satisfy build-dependency.
E: pbuilder-satisfydepends failed.
 -> unmounting dev/pts filesystem
 -> unmounting proc filesystem
 -> cleaning the build env
    -> removing directory /home/buildd/the-pbuilder-way/build//20410 and its subdirectories

exit status 2