I Can't render my video, this is the first time it happened to me, i see this error message

Renderização de /home/joaoguilherme/Vídeos/Vídeos Wolfgam/Fabiano Batata/YTPBR - Revelações do Fabiano Satanista.mp4 falhou
[mp3 @ 0xb918f260] max_analyze_duration reached
[mp3 @ 0xb91a3f60] max_analyze_duration reached
(process:15619): GdkPixbuf-CRITICAL **: gdk_pixbuf_scale_simple: assertion 'dest_width > 0' failed
(process:15619): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_has_alpha: assertion 'GDK_IS_PIXBUF (pixbuf)' failed
(process:15619): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_rowstride: assertion 'GDK_IS_PIXBUF (pixbuf)' failed
(process:15619): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_pixels: assertion 'GDK_IS_PIXBUF (pixbuf)' failed
(process:15619): GLib-GObject-CRITICAL **: g_object_unref: assertion 'G_IS_OBJECT (object)' failed
WARNING: QApplication was not created in the main() thread.
[libmp3lame @ 0xaef1b5a0] channel_layout not specified

Hi Wolfgam,
if it has been working before: Were there changes to your system? Software updates to ffmpeg, mlt, kdenlive? Switched repository? Are mlt, kdenlive and ffmpeg from the same repo? Did you change input formats? Do input files play well with ffplay?
If stuff from above seems to be OK: Which linux distribution are you on (if ubuntuish which repo)? Which output format do you try to render? Does the error appear when trying other output formats (in video and audio)?

Often rendering problems have their root in old libs or incompatible libs (different repos).

I Put something in the start of the timeline, and now works