The first thing you should do is to rule out a corrupted live CD.
You should run the check CD for defects
option from the live CD.
See this: https://help.ubuntu.com/community/In...IntegrityCheck
This will take a minute or 2 to run. If it reports no errors the CD is good.
If it reports errors, then check the md5sums of the Ubuntu iso image that you downloaded: https://help.ubuntu.com/community/HowToMD5SUM
If the md5sum of the downloaded iso image is good, then burn a new CD at the slowest possible speed to avoid errors. If the md5sum of the downloaded iso is bad, then you will need to download a new iso image, preferably from a different mirror.
IF the CD integrity check passes and you still can not install Ubuntu, then write back, because you must have another problem.
Here is a great site for getting started with Ubuntu that is kept up to date: http://psychocats.net/ubuntu/
And welcome to the LQ forums!