I just installed a SharePoint 2010 farm with 3 servers with RTM version. All went well but the next day one of the WFE servers said: Your trial period has expired. Whew …
I called the SharePoint page on the other two servers and it worked. Just on the first server, that hosts central administration, I got the error. But, central administration opened without any issues.
On the web I found this was an issues in the TAP version of SharePoint that remained also in beta 2.
The solution was to add the service account of the application pool of the SharePoint web application to the local adminitrators group on your server.
So I did this, and after an iisreset, the page opened.