I/O error can't copy data after booting from the Disc

[Nikhil]

After booting the ubuntu studio from dvd, I can't copy most of the files to external hard drive. There is a cross sign on uncopied files. Help!

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: xfce4-terminal 0.6.3-1ubuntu1
ProcVersionSignature: Ubuntu 3.13.0-32.57-lowlatency 3.13.11.4
Uname: Linux 3.13.0-32-lowlatency x86_64
ApportVersion: 2.14.1-0ubuntu3.2
Architecture: amd64
CasperVersion: 1.340
CurrentDesktop: XFCE
Date: Wed Jul 8 10:30:25 2015
ExecutablePath: /usr/bin/xfce4-terminal
LiveMediaBuild: Ubuntu-Studio 14.04.1 LTS "Trusty Tahr" - Release amd64 (20140722.1)
ProcEnviron:
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: xfce4-terminal
UpgradeStatus: No upgrade log present (probably fresh install)