Just a note for CB light premium owners:  After the new chesslive.de interface was put up this Spring 2010, my CB light lost access to their online database.  FYI, the following steps fixed my problem as well as getting me a free upgrade to CB light 2009.  Before doing so, back up those databases and layouts!

1.  Deactivate all copies of CB light from the "help" menu under "about chessbase premium 2007".  This is mandatory, per the instructions you never read during install

2.  Uninstall all copies of CB light.  This seems necessary; after i downloaded "chessbase light 2009", my activation key did not work.

3.  Delete all chessbase program folders.  They are usually found in
c:program files  
c:program files(x86)

Although it is probably not necessary, I also deleted all chessbase registry entries and deleted chessbase folders from:
c:\users\*myname*\documents
c:\users\*myname*\appdata\local
c:\users\*myname*\appdata\roaming 

4.  Download Chessbase Light 2007 from http://www.chessbase.com/download/index.asp.  It appears they have intentionally given 2007 users access to the 2009 code from this link.  Your old 2007 activation key works, even though the program is actually 2009.

5.  Reactivate your new installation of CB light.  I was told by support it is perfectly fine to run up to 2 copies under one liscense key.