Can't Install Because It Says It's Not Installed..

So I'm trying to install FFXI on my laptop (I play on my desktop normally) and went through the whole process from the wiki - all good. But I get to the final step where you're supposed to click play and then the game updates and installs. However, when I click play I get Error 020 saying it's unable to start because it's not installed. Well obviously! Quite frustrating so I would appreciate any help.

Did you only install pol and not ffxi?.

yes...

thank you...