This messages means your DLL.XML file was already corrupted before running our installer, probably by some other Addon. Our installer makes first a syntax check using the standard Windows XML library and, if errors are found, it will not touch the XML file.
If you can't find the error yourself (it looks like a wrong tag), you can just remove the file and install the scenery again so, a new correct one will be created.
Of course, if you have other addons that requires a .DLL module in order to work, you will need to reinstall them as well. Eventually, you might find who's corrupting the file during the process.
