Error #2 means somewhere, an ID is being created which begins with something other than a letter of the alphabet.
I would expect the conversion engine to not create those in the first place, but hey, complain to Smashwords. It is their converter.
The fix is to open the HTML and change the ids. As I have no idea how they were generated to begin with (I have no idea how Smashwords' MeatGrinder works
) I have no idea if it is even possible in .doc but it is easy in EPUB.
Error #1 seems to imply that a <span> was simply dumped into the <body> element. It should probably be a div, or at least be wrapped in one.
And once again, without knowing why the MeatGrinder created it that way it is impossible to know how to fix it in the .doc but it is trivial to do so in the EPUB.
Using Styles *might* help, using Styles helps with many things.
Not using Styles is shooting yourself in the foot.
And without an actual EPUB to look at there is no way to be certain of anything we say.