First, Export your patches:
1) Click the part of the Browse panel where it says "All Patches" until you see "My Patches":
2) Select the first patch by single-clicking it.
3) Select all of your patches by scrolling to the bottom of the browse view, and holding down shift while clicking the last patch.
4) With all the patches selected, right click and select "Export [some number] patches"
5) This might take a little while, but when it's done, a Finder window should popup with a .zip file selected in your Desktop folder.
6) If you'd like to verify that all of your patches got exported, you can double-click the .zip file to create a folder - peek in here to verify that there is a .lumenPatch file for each of your patches.
Next, Move your activation:
You can now deactivate Lumen on your old computer by using the Lumen->Show License Info menu item. The license key will also be displayed -- make a note for ease of activating on your new computer.
Finally, Import all of your patches on your new computer:
1) Move the .zip file over to the other computer
2) Double-click it to unarchive it into a folder
3) Launch Lumen
** Note: Lumen has to be activated with your activation code before you can import patches. In case you didn't copy it before deactivating your old machine, you can locate your activation code that was sent to you via email when you bought Lumen by searching for "Paracosm Store" <mailer@fastspring.com>.
4) In Finder, select every patch in the folder you unarchived (you can do this by navigating to the folder and using the Edit->Select All menu item)
5) Drag and drop all of the selected patches onto Lumen's interface.
6) When you release your mouse, after a little while, all of your patches should appear!