Well, this is the Premiere Elements forum.
But in any event, if your serial number isn't working, you'll need to contact Adobe Tech Support and see if they'll issue a new one. (This is a user-to-user forum and we aren't able to do this.)
Or you may want to contact Amazon.com, if this is a used copy of the program. It could be that it's previously been activated.
Though even then, you won't get a message saying the serial number is wrong. Are you sure you're the correct serial number for each program?
Serial numbers for Premiere Elements start with 1143, I believe, and numbers for Photoshop Elements start with 1057.