To back-up your objects.db, you will need to use webOS Quick Install. If you don't have it, download a copy and make sure you have the latest version of Java on your computer. If Java is outdated, grab the new version on java.com, uninstall the old, and load the new.
Once you have that done, put the Touchpad into Developer Mode by entering the Konami code:
in the "just type" box and then clicking the "Developer Mode" icon that will appear.
Plug the mini connector into the Touchpad and open Quick Install. A screen will appear saying that no device is connected. Now connect, and press cancel on the Touchpad when the Touchpad offers the USB Drive mode. Click, click, click OK under Quick Install until the Touchpad is detected, then click "recieve file" and enter the following path:
Select the download location and click ok. Now you should have the file on your computer.
Since i've typed this from memory, if anything is not clear, feel free to ask. I should just write out the proper procedure with screenshots next time and post it somewhere for future reference.