The problem was that, another installer from another product (or if you manually edited the XML file and saved it back without paying attention to the encoding), has changed the encoding of the file from default, which is ASCII with the 1252 Codepage, to UTF8, but with the XML header still specifying a Windows 1252 encoding, basically having an illegal XML.
I've fixed it for you, it was enough to save it in ASCII format with Windows 1252 encoding, which is how the file is supposed to be by default.