not able to install new programs

[eric eaton]

Binary package hint: aptdaemon

An unhandlable error occured
There seems to be a programming error in aptdaemon, the software that allows you to install/remove software and to perform other package management related tasks.
Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/aptdaemon/worker.py", line 961, in simulate
    trans.unauthenticated = self._simulate_helper(trans)
  File "/usr/lib/python2.7/dist-packages/aptdaemon/worker.py", line 1085, in _simulate_helper
    return depends, self._cache.required_download, \
  File "/usr/lib/python2.7/dist-packages/apt/cache.py", line 226, in required_download
    pm.get_archives(fetcher, self._list, self._records)
SystemError: E:I wasn't able to locate file for the ttf-mscorefonts-installer package. This might mean you need to manually fix this package.
1. version 11.04
2. apt-cache policy pkgname returns "unable to locate package name" and I couldn't find it in the Software Center
3. I expected Chromium to install
4. This error
Sorry if this is not the info you need, I am new to Ubuntu.

ProblemType: Crash
DistroRelease: Ubuntu 11.04
Package: aptdaemon 0.41+bzr646-0ubuntu2
ProcVersionSignature: Ubuntu 2.6.38-8.42-generic 2.6.38.2
Uname: Linux 2.6.38-8-generic x86_64
Annotation: Applying software changes failed
Architecture: amd64
Date: Fri Apr 29 08:20:31 2011
DesktopFile: /usr/share/aptdaemon/aptdaemon.desktop
ExecutablePath: /usr/sbin/aptd
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Release amd64 (20110427.1)
PackageArchitecture: all
SourcePackage: aptdaemon
Title: <type 'exceptions.SystemError'>: E:I wasn't able to locate file for the ttf-mscorefonts-installer package. This might mean you need to manually fix this package.
TransactionDepends: [[], [], [], [], [], [], []]
TransactionErrorCode: error-unknown
TransactionKwargs: {}
TransactionLocale: en_US.UTF8
TransactionOutput:

TransactionPackages: [[dbus.String(u'chromium-browser')], [], [], [], [], []]
TransactionRole: role-commit-packages
UpgradeStatus: No upgrade log present (probably fresh install)