Need to copy FCP to Mac Pro... Have serial, but Discs lost

I have a registered copy of final cut pro 7.0.3. It is installed on my laptop. My laptop isn't working anymore, but I have a backup of all the files. I have a mac pro that I can use, however I cannot find my install discs anywhere. I do have my serial number written down somewhere. I would like to copy final cut to the mac pro from the back up of my laptop that I have, but I get an error. Something to do with it not working because of the version of OSX. I know this can't really be a problem because the laptop and Mac Pro were on the same version. What can I do to successfully copy it?