Calibre Portable question

I'm going to be away from my home computer for 2 weeks, so of course I want to bring my Calibre library with me. I've installed Calibre Portable on a memory stick, and copied my library into the Calibre Library folder, per the instructions on the blog, but when I open Calibre Portable, it doesn't see my books.

Do I have to reload all my books? or is there a file (the metadata.db file?) that I need to copy over? except that my library on my home computer is in a different directory than the directory in Calibre Portable.

There's clearly a step I'm missing - can someone help?

thanks,

Becca