When trying to open an .AVI video file, the error "Attempt to open /home/luis/video/freebsd.avi failed!".
Please run avidemux3_qt5 on command line and redirect the stdout and stderr to a file, reproduce the problem, close Avidemux, then compress the generated text file and attach it to your reply.
avidemux3_qt5 2>&1 | tee ~/admlog.txt