Okay, so...
You don't need the Cache Builder for a Pearl 2008. Starting with the 2008, the personality structure is different, which reflects in the available downloads at
http://personalities.avolites.com/ (scroll down to 'other personalities').
The best way for you would be:
- download one - or both - installers for Pearl 2008/2010/Tiger
- run it on your PC
- then, in the resulting file structure, you may delete all files you decide not to need
- then, transfer the files (in the correct folder structure) to a USB stick
- on the desk, you might want to delete all personalities: System -> USB Stick options -> Wipe Fixtures
- then, bring the personalities from your stick into the desk: System -> USB Stick options -> Sync Fixtures
It's described in the manual:
http://www.avolites.com/LinkClick.aspx? ... 99&mid=511 page 201/202, section 13.1.2