Google Browser Sync - signing could not be verified

My colleague has suggested Google Brower Sync for sync'ing bookmarks on different computers. By installing this Firefox extension, it manages the bookmarks, history, passwords using my Google account for central storage. That sounds good to me, as I have over 100 bookmarks accumulated over 8 years, and I had problem in keeping them in sync with my Office and Home PC (and my iBook as well). Recently, I has been using import/export bookmark function to keep them in-sync, but it is very time consuming in managing those bookmarks as I need to reorganize them in a better order for each import.

I can manage to install it on the Firefox of my Office PC, but my Home PC doesn't. After downloading the extension. Firefox complains about "Signing could not be verified" and stopped the installation. I have reviewed the options/preferences in Firefox, test with diferent certification setting and get no idea. Searching on google and following some troubleshooting instructions and I am still getting nowhere. Now, Google Browser Sync is of no use to me, as I only get one PC working... I will try it on my iBook later.