Just take a look at my dll.xml files and you see!!!
There's nothing wrong with your dll.xml file after the KSFO installation (which is the same installer as FSDT anyway), it would have been easier for me to check, if you posted the actual file here, instead of a screenshot of it.
However, it doesn't seems wrong, it's just not cleanly formatted, which still indicates something wrong happened during the installation (because we run a reformatting tool at the end of the install to clean up that file). However, not being cleanly formatted it's not a problem at all with an XML file since, the whole point of an XML file is not being dependent on formatting: as long as all the tags are properly open/closed, the file is still a legal XML file and will be parsed correctly by FSX. The only reason why we run a reformatter to clean it up at the end, it's ONLY because OTHER 3rd party installer, that are unable to deal with XML files properly, and mistakenly threat them as being text files, can be confused, which is why we clean it up at the end.
For some reason, yours haven't been cleaned up (perhaps the antivirus has even killed the reformatter...which is absurd, considering it's a standard W3C utility) but, as I've said, the file is correct.
If it wasn't, you wouldn't see ANY 3rd party module. If you see the Addon Manager menu, it means the DLL.XML is OK.
Which is why I asked to check for COUATL instead. Do you see its menu ? The Couatl program is in the EXE.XML, not in the DLL.XML.