When setting up the program, at the user info screen, it's asking for a serial number. Where do I get this serial number from?
Unfortunately, according to the developer's website, the application that you're looking for has been discontinued all the way back in 2011, which means that you can no longer purchase it to get a serial number.
However, on the previously mentioned web page the manufacturer also states that DAQSIGNIN has been replaced with Button Operated DX1000/DX2000, so you may want to check that product out and see if it helps you.