I had a problem trying to copy and paste the licenses into the boxes in the registration page, using either the ctrl-c/ctrl-v or the windows shell copy/paste (mouse). I worked around it in short order.
W7/x64
Copying/Pasting registration numbers
I assume you mean copy all three fierlds in one go to the three ffields in the registration dialog, that cannot currenlty be done, you have to paste each field one at a time.
But it is a good idea and I have raised the following issue http://jthink.net:8081/browse/SONGKONG-138