The keys are version specific and the demo version of Active@ Partition Recovery you are using may be slightly out of date. There is an easy way to get around this issue. If you have performed a SuperScan which took some time, you may save the scan results to save you from doing a lengthy scan again.
So save the scan results by highlighting the scan results on the left side of the screen and select File - Save Scan results.
Then close the Partition Recovery program.
You will then need to refer to the link in the email you received which contained your registration keys and download link.
Download that setup program and install the software.
Launch the newer Active@ Partition Recovery and from the Help - Enter Registration Keys, cut and paste your registration keys in.
They should be accepted and you can then return to your previous scan results by selecting the Drive you scanned on the left hand side of the screen and then select File - Open Scan Results. The Scan Results will load back in and you can continue to use the program in full mode from that point on.