You seem to have an illegal character at the beginning of the XML file. When I view source in Chrome it shows a dot before <?xml
I copied that and searched the character map, turns out it's the character U+FEFF ZERO WIDTH NO BREAK SPACE. So it's likely a problem with file encoding or conversion. I think I had something like this before (not with Q2A, some other software) and I just went through all the files and hit delete on the first character to make sure there was no hidden character there.
You could also try searching the files using something like Notepad++ in case that character got in there somewhere. Or try converting the offending files all to the same encoding.