I hope that this isn't a RTFM problem, because it is so basic, why should I be the first to encounter it?
The renderer produces a short invalid file as soon as I add a title clip.
The setup: Ubuntu 12.04, 64 bit, first with the "standard" kdenlive version (0.8.something) - I since updated to the sunab ppa, i.e. 0.9.4.
I start kdenlive from the command line using
export LANG=C; kdenlive
to get the english menus etc.
I add a clip and change the profile to the suggested one (depending on the resolution).
I pull the clip to the timeline (Video 2), expand the selected range to fit the entire clip, press "Render", "use selected zone", "render to file".
The rendered clip works perfectly.
I add a title clip, enter some text.
I put that clip on the timeline (Video 1) at position 0. kdenlive automatically adds the transition "Affine".
The "project monitor" shows the expected result: some text put over the clip.
I hit render...
The render finishes immediately. The resulting file is 0 bytes long.
The terminal output of the two renders looks quasi identical, except for the line "NULL item." before "//STARTING RENDERING:" in the second one.
The melt -version is 0.8.8.
I tried various input formats, various output formats, all with the same (i.e. no) result.
P.S.: It there a "thank you, developpers"-thread somewhere? :-)