Andrea,

I tried with various tiff settings and other profiles (png and DPX)
with the same result. If instead of ffmpeg I use the internal engine I
get the expected result: the file list is complete with links to the
various image-frames and the loading in CinGG is successful. Tried
with tiff, png and openexr.
Does it work for you to render image sequences with ffmpeg?

My tests agree with yours, i.e. you must use CinGG's internal engine and I checked the manual to ensure it was clear that you have to not use ffmpeg. However, I am going to work on testing ffmpeg today to see if I can get it to work somehow -- first I have to be able to get it to work from the ffmpeg command line.