I just came back and rather than delete this post, I wanted to mention what I did in case anyone is still having problems.
I just changed my preferences in the Adobe Application Manager and moved the location of the download to another drive. and all is well now.
Seems that it is big and since I had it safely in one folder before, I must have downloaded other things afterward which maxed out my folder and would NOT let me download the upgrade.
That might help someone else.
And again, I'm back... I also had to tell my Norton 360 software to allow Muse to do its thing. I was still having a few issues getting the 2.1 upgrade to open before I did that.