* Double, triple, quadruple check you username and API key. This
fixes 95% of problems.
* Restart Firefox.
* Uninstall and reinstall the extension.
* If you have a multi-user Backpack account, then the user name in the
extension is actually the xxx in http://xxx.backpackit.com and not the
individual's user name. They used to be the same thing before
multi-user accounts. I need to reword the option in the extension to
eliminate confusion.
Please let me know if you're still having problems after trying all of
the above.
Thanks,
Ben