Visioneer paperport serial number is wrong

I have Scansoft Paperport 7300 for visioneer OneTouch. It was previously installed by me, but I had to reinstall. However, when it asks for the serial number of the scanner, it won’t accept it–too many digits. I have tried leaving out numbers, etc. to no avail. It is an end of life scanner so their tech support won’t help. I downloaded the program and it still wants the serial number. How do I get or trick it into installing?