Audio and video are out of sync for some videos.
The FAQ'S on the page at http://www.videolan.org/support/faq.html give the solution as 'Try using another audio output plugin and, under Unix, kill esd, artsd or pulseaudio if they are running. If the problem is due to the input file, have a look at the "Audio desynchronisation compensation" option'.
This answer is as much use as a chocolate teapot (I looked through everything I could think of trying to find 'unix or esd' or whatever, and got nothing. I couldn't even find 'audio output plugin'.
If you are going to answer the question properly then you should make the solution more detailed by giving a step-by-step list of instructions using screenshots of the pages seen on the way to the final page wanted (with say red rings circling the relevant locations of items mentioned in the instructions).