builders badly broken.. sudo syntax error

since yesterday, my i386 PPA builds end up in CHROOTWAIT mode.

Logs start with:

========
RUN: /bin/echo ['echo', 'Forking build subprocess...']
Forking build subprocess...
RUN: /usr/share/launchpad-buildd/slavebin/unpack-chroot ['unpack-chroot', '098c81d5a573daa43421561a5a8dbb12c3860251', '/home/buildd/filecache-default/d07a71733518179e223854cc698007b6272c37c0']
Uncompressing the tarball...
Synching the system clock with the buildd NTP service...
sudo: /etc/sudoers.d/buildd is mode 0644, should be 0440
>>> /etc/sudoers.d/README: /etc/sudoers.d/buildd near line 18 <<<
sudo: parse error in /etc/sudoers.d/README near line 18
sudo: no valid sudoers sources found, quitting
*** glibc detected *** sudo: double free or corruption (!prev): 0x0000000000629ff0 ***
======= Backtrace: =========
/lib/libc.so.6[0x7f7a3330b0ea]
/lib/libc.so.6(cfree+0x8c)[0x7f7a3330ec7c]
/lib/libc.so.6(fclose+0x14c)[0x7f7a332f9e0c]
sudo[0x4101db]
sudo[0x4111b6]
sudo[0x40efea]
sudo[0x4124db]
/lib/libc.so.6(__libc_start_main+0xf4)[0x7f7a332b51c4]
sudo[0x403659]
======= Memory map: ========

...

see
https://launchpadlibrarian.net/77585055/buildlog_ubuntu-maverick-i386.chromium-browser_15.0.857.0~svn20110819r97408-0ubuntu1~ucd1~maverick_CHROOTWAIT.txt.gz