Zoomerang Surveys in Firefox

Currently running a survey using Zoomerang. I've found that it doesn't work within Firefox on a Mac. (It may not work on other versions of Firefox either, but that's the one complaint I have.) I emailed Zoomerang only to be told that they often have problems with Firefox and I should be using Internet Explorer. This makes NO sense, given that Firefox holds a significant market share. This creates a lousy customer experience for my users.