When Captivate publishes HTML5, it doesn't work in Firefox. Captivate exports only MP3 audio, and Firefox only plays OGGs. This post provides some tweaks for the Javascript to get rid of the error message and look for OGG versions of the file when needed. You have to create both versions of the audio files.
Open Source screen reader for Firefox. Nice to have a free option that you can use for development and testing purposes without violating the TOS (i.e., JAWS).
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