Ubuntu 10.10 Live CD - How to copy files to external USB drive (no permissions?)

Question

I booted up an Ubuntu 10.10 live CD and plugged in an external USB hard drive. It brings up the drive contents and shows all the files, but it won't let me copy files to the external USB drive.

It says

Error while copying

The folder ... cannot be copied because you do not have permissions to create it in the destination.

What should I do to be able to put files on it?

Update, I'm not sure if this helps but I ran mount -l and got this:

ubuntu@ubuntu:~$ mount -l
...
/dev/sdc1 on /media/ext_backup type ext3 (rw,nosuid,nodev,uhelper=udisks) [ext_backup]

Answer 1

sudo chown Username /media/usbdisk

I would also add a -R so it operates on all files and directories.