Thank you for posting that link!
I have become VERY familiar with it because somewhere in there lingers that one little word which just might fix my problem.
To have others look at what might be the issue, I am posting the "relevant" lines here BUT I am checking each line which you have written in the Manual (MIME types for HTML5 games)
System MIME Types
01 text/html : .shtml .shtml .shtml .shtml html htm shtml
03 audio/ogg : oga ogg spx
04 video/webm : webm ?? > C2 manual states ".webm"
05 video/mp4 : mp4 mp4v mpg4 (no dot!)
06 text/csv : csv (no dot)
07 application/json : json (no dot)
08 image/svg+xml : svg svgz
09 application/pdf : pds (no dot)
10 application/octet-stream : bin dms lha lrf lzh so iso dmg dist distz pkg bpk dump elc deploy
User Defined MIME Types
21 audio/mp4 : .m4a m4a (with and without dot)
22 text/cache-manifest : .appcache
23 application/font-woff : .woffe
24 application/x-web-app-manifest+json : .webapp
25 application/manifest+json : .manifest
26 text/xml : .xml
Upon closer examination, I see the some extensions have missing dots.
What I will do now:
Change the URL for a game (make a new dir/subdir and see if it works????)
It would be awesome to get sound working in IE but if the new directory/upload doesn't fix it I will talk to a new host, and ask if they can give me a 24 hr test account.
Sound in IE is the last hurdle to be fixed before school starts again.