Here is a network troubleshooting help page. Go thru the steps in this link and check the Hosts file. If your computer can not communicate with the Adobe activation servers. Often you can receive an invalid serial # error
Are you trying to install Lightroom 5? If you are, then download the most recent Lightroom 5.7 update from here and install the software.
Let me know if this works or not
I figured it out. I was confusing a 0 for an O. thanks