May I ask how this file was created? There are some different types of files who share the same extension: .XML. In TBC, we only support the LandXML format, which is usually used as an exchange format among TBC, AutoDesk, and Microstation.
I tried to open your file in C3D, and got an error message saying this is not a LandXML format, that's why TBC doesn't read it either.
Hope it helps. Thank you.