Licensing for this product has stopped working

[yosale]

I have PP ver CS4 on my mac (Mavericks 10.9.2) that I have purchased and used until recently. All of a sudden when I try to run it, I get the above message.
Any ideas how to get my software to work again?
Thanks,
Joe

[Bob]

See this: http://helpx.adobe.com/x-productkb/global/error-licensing-stopped-mac-os.html