Hi,
1. You should run RAM test on your laptop to test that your RAM is intact.
2. Or you can also try to remove one of your DDR chips if you have any extra chips inserted in your laptop.
3. One solution I found from the web is to press "Cancel" after that error and press "Install now" again (without rebooting) and to hope that the error doesn't appear this time.
4. If those doesn't work and you are installing downloaded ISO that you have burned to DVD / installing from USB the ISO file may be corrupted. In this case you should try to redownload the ISO file and reburn it.