Thank you very much for the prompt reply. I actually did a clean reinstall and then I attempted your solution, and it worked like a charm... or so I thought. I tried to use the original, un-normalized track again so I could reproduce the error for you, but I couldn't reproduce it. I also did a Java update as part of my search to correct the error. Either way, now, both the normalized and un-normalized tracks are working fine in Firefox.
I'm sorry for the trouble- from what I can tell, audio issues are commonly the browser's fault rather than Construct, so I'm sure you get sick of hearing about them :)
If I can reproduce the problem, I will post about it again with the capx file.
Once again, I really appreciate the assistance.