Upgrade doesn't work

[rraike]

..I am trying to upgrade my hoster from 2.011 to 2.014. When I install the program and use the registration code that I was given, it says that the code is already in use by another computer..and fails. I changed my email address late last year and informed MTU and I was wondering if the code generated is on the old address that i originally purchased hoster on, or the new one. Either way it doesn't work.
Also do you have enter info Name address etc EXACTLY on the first page. Is a registration code and a serial number the same thing or am I missing something ?
Anybody got any ideas. Thanks