cd version number warning (9.1)

[max21]

I inserted the FreeBSD 9.1 cd to install some packages and this is what I got:

User Confirmation Requested

Warning: The disc currently in the drive is either a FreeBSD disc or and older (pre 2.15) FreeBSD CD which does not have a version number on it. Do you wish to use this disk anyway?

Since 9.0 and 9.1 kernel will not compile for me I dumped 9.0-current to start using 9.1 since I can't win anyway .. This is the version number department, right? Why am I'm getting this warning?

uname -a:
FreeBSD test-91.example.com 9.1-RELEASE #0 r243825:  Tue December 4 09:23:10 

UTC 2012 ... amd64