@StarFleet CarlWhile most ePubs are dependent on browser coding to operate, there is no requirement that the various browsers need to automatically open them. Tell your pal to search for an ePub reader Firefox plug-in (I haven't used FF in years, so the one I used to use is likely no longer functional any more). That should take care of your friends ability to access the ePubs. Most OSes generally have their own ePub readers, though each one calls their something slightly different, so you'll need to Google to fine out what it is (this is essential for testing your ePub files).
The odd symbol in place of the smart quotes (inward facing single and double quotation marks) result from your mistakenly formatting it incorrectly. All ePubs need to be formatted as UTF8, using the following line in the Header Section at the top of each html file used to compile the ePub (Note: You can't just change the text, you'll have to reformat the file to change the file type).
< meta http-equiv=Content-Type content="text/html; charset=utf-8">
However, before you do that, you'll have to manually replace each smart quote, any accented character (i.e.foreign phrases in your story) as well as any 'publishing' character (i.e. em-dashes and ellipses), so that they'll appear correctly in the new document. You can automate this process, but I'm not aware of any automatic conversion tools for them.
Once you've converted all those 'special characters', you can now do one of the following: either use a conversion tool (ex: Lazeez directed me to BBEdit, which handles this wonderfully) or simply create a new UTF8 html file and copy the converted text and paste it into the new file.
It's the new UTF8 html file that you'll need to submit to Calibre to both create the required ePub file, as well as to convert it into variety of other eBook formats.
Last but not least, you'll need to use Calibre to generate a list of ePub errors for you. Despite hand-crafting each of my files and stripping out all the kludgy 'legacy' code, I'll typically generate anyone from 5 to 20 errors on each of my ePubs each time I update a given ePub, so it's a fairly tedious process.
In Calibre you'll need to click on the "Edit Book" symbol at the top of the page (it's the purple book image just after the peach-colored "Remove books" icon). This will pop up a VERY complex tool, but in the upper right hand corner, you'll see a "Run check" link. If you press this, it'll generate a list of ALL the errors in your ePub.
Once you do this, click on each of the items highlighted in the upper left column (one at a time, of course). That same upper right Error column will list specifically what the error is, which section (chapter) it is, and an explanation of the error. Simply click the blue link and it'll fill in the bottom sections with the individual chapter's html file and highlight the line which generated the error.
You can try to click the "Try to correct all fixable errors automatically", but this typically will only fix a few, as the vast majority of ePub errors are automatically generated by the Calibre conversion process itself (where it converts your clean html code into the nonsensical Calibre paragraph types).
Fix whatever you can and then click on the "Re-run check" to see how many still remain, and keep doing this until you get a 'clean' copy. Note: you'll have to do this whole procedure every single time you update your existing ePub file, so you'll likely spend more time in Calibre's EDIT BOOK function than you did creating the html files to begin with.
Once you get used to that, either check back in here or send me a PM and I'll tell you which defaults you'll need to set for each specific document type, as Calibre's settings are pretty brain dead, and you'll need to manually activate the features of each format (i.e. epub, mobi, and pdf). But for now, that's best left until you get a clean ePub.
Good luck, and trust me, this process NEVER gets any easier, but so far, I've yet to meet a satisfactory ePub generator!