can't login withough manually modprobing ecryptfs

Binary package hint: gdm

I can't login with GDM: I type my username, hit enter and then it empties the username field to start over, i.e. it doesn't ask me for my password or my fingerprint.
After switching to a terminal, modprobe ecryptfs and switching back to X, I am asked to enter my password or my fingerprint.

FWIW: I manually created a key with ecryptfs-manager:

muelli@xbox:~$ find .ecryptfs/
.ecryptfs/
.ecryptfs/pki
.ecryptfs/pki/openssl
.ecryptfs/pki/openssl/key.pem
muelli@xbox:~$ grep -v '#' /etc/pam.d/common-auth

auth sufficient pam_thinkfinger.so
auth [success=1 default=ignore] pam_unix.so try_first_pass nullok_secure
auth requisite pam_deny.so
auth required pam_permit.so
auth optional pam_ecryptfs.so unwrap
muelli@xbox:~$

I'll attach my gdm.log and a trunctated version of my auth.log

ProblemType: Bug
Architecture: amd64
DistroRelease: Ubuntu 8.10
Package: gdm 2.20.8-0ubuntu1
SourcePackage: gdm
Uname: Linux 2.6.27-4-generic x86_64