Originally Posted by mikelv
Is the file protected by DRM? If so, you can't use my addon to read it. In this case you need a reader which supports DRM, e.g. Adobe Digital Editions.
What's the extension of the filename? "epub"? If not, please rename it to "*.epub" and try it again.
It's just an ePub from here at Mobile Read, no DRM involved. I'm going to try the plug-in on my work computer, FF 3.5.3, and see how that works.