Hmm, did you already reinstall Scrapbook? It sounds as though you could try replacing its new folder and settings file with the ones from your backup.

Where are my collected data stored?

They are stored in 'ScrapBook' directory in your profile folder. The file named 'scrapbook.rdf' is a XML/RDF that manages tree structure of your collection, and each items you collected are in 'data' directory.

I don't want to store collected data in my profile folder. I want to change the destination to store data.

First, move entire 'ScrapBook' folder to your favorite location. Then go to [Tools] > [Settings] > [Advanced], configure the [Destination to Store Data].

From: http://www.xuldev.org/scrapbook/misc.php

To open your currently active Firefox profile folder, the easiest way is to start from inside Firefox. Open the Troubleshooting Information page using any of these methods:

• "3-bar" menu button > "?" button > Troubleshooting Information
• Help menu > Troubleshooting Information
• type or paste about:support in the address bar and press Enter

In the first table, click the "Show in Finder" button. Firefox will launch your current profile folder in a Finder window.

As for where your old profile folder is in your backup, I'm not quite sure how best to find it. (I'm a Windows person myself.)

Windows doesn't help me. Thank you though. I need help with the Mac.

gigglez said

Windows doesn't help me. Thank you though. I need help with the Mac.

Yes, obviously! Hopefully once you find the correct data in your Time Machine the other steps I provided will help you place it in the relevant location.