update-apt-xapian-index crashed with OSError in <module>()

Binary package hint: apt-xapian-index

Description: Ubuntu intrepid (development branch)
Release: 8.10

apt-xapian-index:
  已安装：0.15
  候选的软件包：0.15
  版本列表：
 *** 0.15 0
        500 http://ubuntu.cn99.com intrepid/main Packages
        100 /var/lib/dpkg/status

This error was happened while I was starting up synaptic without root, but synaptic seems worked normally.

ProblemType: Crash
Architecture: i386
DistroRelease: Ubuntu 8.10
ExecutablePath: /usr/sbin/update-apt-xapian-index
InterpreterPath: /usr/bin/python2.5
Package: apt-xapian-index 0.15
PackageArchitecture: all
ProcAttrCurrent: unconfined
ProcCmdline: /usr/bin/python /usr/sbin/update-apt-xapian-index -q
ProcEnviron:
 SHELL=/bin/bash
 PATH=/home/username/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games
 LANG=zh_CN.UTF-8
PythonArgs: ['/usr/sbin/update-apt-xapian-index', '-q']
SourcePackage: apt-xapian-index
Title: update-apt-xapian-index crashed with OSError in <module>()
Traceback:
 Traceback (most recent call last):
   File "/usr/sbin/update-apt-xapian-index", line 511, in <module>
     lockfd = os.open(XAPIANDBLOCK, os.O_RDWR | os.O_CREAT)
 OSError: [Errno 13] Permission denied: '/var/lib/apt-xapian-index/update-lock'
Uname: Linux 2.6.27-2-generic i686
UserGroups: adm admin audio cdrom dialout dip floppy fuse lpadmin plugdev vboxusers video