Badly formed XML, there is no tag

Using glade-3 i got with this error/warning:

[walter@talent Projects]$ gtk-builder-convert uno.glade uno.xml

Traceback (most recent call last):

File "/usr/bin/gtk-builder-convert", line 772, in
sys.exit(main(sys.argv))
File "/usr/bin/gtk-builder-convert", line 760, in main
conv.parse_file(input_filename)
File "/usr/bin/gtk-builder-convert", line 161, in parse_file
self._parse()
File "/usr/bin/gtk-builder-convert", line 233, in _parse
assert glade_iface, ("Badly formed XML, there is "
AssertionError: Badly formed XML, there is no tag.

Try saving the file as a libglade project and then try again. It work'd for me.