I downloaded the free version of DVX Audio Enhancer and then purchased DFX Plus Masterpack and downloaded it. The audio enhancer control panel is still in "free" mode (restricted controls) and when I try to resister with the serial number they emailed me, I get an error message that says, "illegal serial number." The company's emails are coming from "unknown sender" and the response time from the company is horrible. Any suggestions? Thank you.