package management - ubuntu-restricted-extras

I am trying to install ubuntu-restricted-extras on Ubuntu 14.04 LTS (so that I can play mp3 files). However, I get an error message (see below). Any suggestions? Thanks!

 ...$ sudo apt-get install ubuntu-restricted-extras
[sudo] password for ***:
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following extra packages will be installed:
  freepats gstreamer0.10-fluendo-mp3 gstreamer0.10-plugins-bad
  gstreamer0.10-plugins-bad-multiverse gstreamer0.10-plugins-ugly
  gstreamer1.0-fluendo-mp3 gstreamer1.0-libav gstreamer1.0-plugins-bad
  gstreamer1.0-plugins-bad-faad gstreamer1.0-plugins-bad-videoparsers
  gstreamer1.0-plugins-ugly liba52-0.7.4 libass4 libavcodec-extra libcdaudio1
  libchromaprint0 libdca0 libdirac-encoder0 libdirectfb-1.2-9 libdvdnav4
  libdvdread4 libenca0 libfaac0 libfaad2 libflite1 libfluidsynth1 libgme0
  libgstreamer-plugins-bad0.10-0 libgstreamer-plugins-bad1.0-0 libkate1
  libmad0 libmimic0 libmjpegutils-2.1-0 libmms0 libmodplug1 libmpcdec6
  libmpeg2-4 libmpeg2encpp-2.1-0 libmpg123-0 libmplex2-2.1-0 libofa0 liboil0.3
  libopenal-data libopenal1 libsidplay1 libslv2-9 libsoundtouch0 libspandsp2
  libsrtp0 libts-0.0-0 libtwolame0 libwildmidi-config libwildmidi1 libzbar0
  libzvbi-common libzvbi0 oxideqt-codecs-extra tsconf ubuntu-restricted-addons
Suggested packages:
  frei0r-plugins libchromaprint-tools python-acoustid libdvdcss2
  libroar-compat2 sidplay-base xsidplay slv2-jack srtp-utils
The following packages will be REMOVED:
  oxideqt-codecs
The following NEW packages will be installed:
  freepats gstreamer0.10-fluendo-mp3 gstreamer0.10-plugins-bad
  gstreamer0.10-plugins-bad-multiverse gstreamer0.10-plugins-ugly
  gstreamer1.0-fluendo-mp3 gstreamer1.0-libav gstreamer1.0-plugins-bad
  gstreamer1.0-plugins-bad-faad gstreamer1.0-plugins-bad-videoparsers
  gstreamer1.0-plugins-ugly liba52-0.7.4 libass4 libavcodec-extra libcdaudio1
  libchromaprint0 libdca0 libdirac-encoder0 libdirectfb-1.2-9 libdvdnav4
  libdvdread4 libenca0 libfaac0 libfaad2 libflite1 libfluidsynth1 libgme0
  libgstreamer-plugins-bad0.10-0 libgstreamer-plugins-bad1.0-0 libkate1
  libmad0 libmimic0 libmjpegutils-2.1-0 libmms0 libmodplug1 libmpcdec6
  libmpeg2-4 libmpeg2encpp-2.1-0 libmpg123-0 libmplex2-2.1-0 libofa0 liboil0.3
  libopenal-data libopenal1 libsidplay1 libslv2-9 libsoundtouch0 libspandsp2
  libsrtp0 libts-0.0-0 libtwolame0 libwildmidi-config libwildmidi1 libzbar0
  libzvbi-common libzvbi0 oxideqt-codecs-extra tsconf ubuntu-restricted-addons
  ubuntu-restricted-extras
0 upgraded, 60 newly installed, 1 to remove and 8 not upgraded.
Need to get 851 kB/50.2 MB of archives.
After this operation, 86.3 MB of additional disk space will be used.
Do you want to continue? [Y/n] y
Err http://archive.ubuntu.com/ubuntu/ trusty-updates/main oxideqt-codecs-extra amd64 1.5.6-0ubuntu0.14.04.2
  404  Not Found
Err http://security.ubuntu.com/ubuntu/ trusty-security/main oxideqt-codecs-extra amd64 1.5.6-0ubuntu0.14.04.2
  404  Not Found
E: Failed to fetch http://security.ubuntu.com/ubuntu/pool/main/o/oxide-qt/oxideqt-codecs-extra_1.5.6-0ubuntu0.14.04.2_amd64.deb  404  Not Found
E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?

My configuration in "Software & Updates" is as follows: everything is checked under "Downloadable from the Internet" (including the last item "Software restricted by copyright or legal issues (multiverse)"), and I have "Download from: Main server".