Just to let you know that downloading and applying the ra-codec12.zip file, and then recreating the MP3Encoding registry entries worked. I can now record straight from Audio CD to MP3 using Media Player 9.
Click Start, Run, type: regedit and press Enter. Now click registry, Export, select all and save a copy of the registry to the desktop. Still in the editor, use the + signs next to the folders to navigate to the following key:-
If any of these don't exist (quite likely for Settings and MP3Encoding) create them as new keys.
Under the MP3Encoding key you need to create some settings values, so highlight the MP3Encoding folder, and in the righthand pane you'll see only a default item. Right click the pane and select New, Dword, then rename the new icon that appears to LowRate exactly as shown. Now double-click LowRate and in it's edit box enter the value 0000dac0 exactly as shown and click OK.
You need to repeat this 3 more times, renaming and giving values for each, so that you end up with the following 4 icons and values in the right-hand pane.
Now close the registry and go straight to Media Player 9. Click Tools, Options, Copy Music tab, and you'll now find that mp3 has been added to the Format: drop-down menu.