Can you give an example of a "valid" tvshow.nfo xml?
There are good examples of nfo files here:
I named my movie files S01E01-filename1, S01E02-filename2, etc. and put them into a folder.
Then ran Yang to generate the movie nfo files (nfo files with the same exact name of the movie file). After Yang created the nfo files, I went in and
edited them with Notepad to suit my taste.
I then created the tvshow.nfo file in a text editor (Notepad) and dropped it
into the folder of the above movies.
Mine was like: Seinfeld/ Season 1/ movie files. The tvshow.nfo went into the Seinfeld folder. The individual movie nfo files go into the Season 1 folder with all the movies for that show.
Then I updated the TV library through XBMC, it picked up the shows and it all worked out.
Hope this helps