update-manager crashed with SIGSEGV in PyEval_EvalFrameEx()

First use - clean install - daily build 12.04 (2012.04.11). Update manager crashes with:

update-manager[7238]: segfault at 398e8c6 ip 00007fcd5820621b sp 00007fffaca9d940 error 4 in apt_pkg.so[7fcd581df000+4a000]

Also, cannot easily report this bug as it fails with:

"This is not an official Ubuntu package. Please remove any third party package and try again."

despite being a clean install and first use.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: update-manager-core 1:0.156.10
ProcVersionSignature: Ubuntu 3.2.0-23.36-generic 3.2.14
Uname: Linux 3.2.0-23-generic x86_64
ApportVersion: 2.0.1-0ubuntu1
Architecture: amd64
CasperVersion: 1.314
Date: Wed Apr 11 19:05:29 2012
GsettingsChanges:
 com.ubuntu.update-manager first-run false
 com.ubuntu.update-manager launch-time 1334169675
 com.ubuntu.update-manager show-details true
LiveMediaBuild: Ubuntu 12.04 LTS "Precise Pangolin" - Beta amd64 (20120411.1)
ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: update-manager
UpgradeStatus: No upgrade log present (probably fresh install)