I had the same problem today with my 2012 to 2014 upgrade. It was mentioned and stressed so many times that you NEED A PREVIOUS SERIAL NUMBER FOR THE INSTALLATION, that I was completely focussed on my old (Poser 2012 Pro) Serial number. I entered it four or seven times, first believing in a mistyping, then exchanging zeros and capital o's systematically... Finally I reallized that I had already received a new serial number for the 2014 upgrade, and that I had to enter my new serial number first, and later the former one...

From the point of view of software ergonomics it would be helpful to add "Poser Pro 2014" to the input message, making it:

'Please enter your Poser Pro 2014 serial number'

 

Really, I was close to sending mails to customer support myself, just like 3dcheapskate above.

Poser Pro 2014 GameDev, Lightwave 11.6.3, Blacksmith3D Pro 6, Bryce 7, Carrara Pro 8.5, Reality 4 & LuxRender, Python 2.7 & Wx-Python, UV-Mapper Pro, XFrog 3.5, Paintshop Pro X7, Apophysis 7x64

-  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -

Don't render faster than your artistic guardian angel can fly...