Recording on Ubuntu+Firefox+Java
If you're having trouble with Audioboo's browser recording on Linux, you should ensure that you're using Sun Java 6, rather that OpenJDK. You can install this by following these steps:
Open up Ubuntu Software Center and go to Edit > Software
Sources, then on the "Other Software" enable the Partner
repository.

Back in the Get Software section, search for 'java6' and install
the Java Plugin

Finally, you need to tell firefox (and the rest of your system)
which Java to use. Open up Terminal, and run 'sudo
update-java-alternatives -s java-6-sun'

After restarting Firefox, you should be able to record.
sources: