What version of Firefox are you running and on what system? Here we run Firefox 2, Firefox 3 RC2 and Firefox 3 released edition and we have done testing on all these. Between Firefox betas and RC2, the mozilla team made changes that affected our toolbar and we had to keep making changes to keep up. So, if you are running an older version of Firefox, that might be one problem.
Otherwise, it should work and we'd like our engineers to be able to get in touch with you to figure out what's going wrong in case other people are seeing the same thing but not reporting it. So, could we either contact you via the email with for the web site or could you send an email to support@eluma.com with a contact email and we will have someone contact you directly?