Hi Ashley, thanks for the response (And thanks for making Construct 2! :D ).
I actually had only m4a files and just added a batch of ogg duplicates in this update. The IE sounds work now on the desktop after rebooting my computer, exporting again and uploading. But sound is intermittent on my Windows Phone and Tablet. This goes for both sfx from the Sound folder and songs from the Music folder.
EDIT: the sound on the desktop stopped working again with no changes from my side. It's happening off and on. Maybe the problem is with my server's streaming--but then safari and firefox always work. Regardless, I will test hosting it elswhere.