Go to the "Help" dialog while using any plug-in to determine if your trial or temporary license has expired. If so, then you need to acquire and enter a valid license. Once you receive the valid license and activate it, the results should return to normal.           
                                                                           
If you have a license that has not expired, review the following:

1. Ensure you have run the GenArts installer on your machine, rather than cloning, ghosting, or copying files from another workstation. If you installed the software by copying, then download and re-run the installer;
2. Ensure the date on your computer is correct;
3. If the Ethernet address of your computer has changed since you ran the installer, then re-install the software and re-enter your serial number.