Oh my, there's so much misinformation around VLC for OSX...
Many suggest that lua extensions have to go here:
* Mac OS X (all users): /Applications/VLC.app/Contents/MacOS/share/lua/extensions/
(In fact, mederi, that appears from your own code, see here:
http://addons.videolan.org/content/show ... ent=149688)
However, this is not a good place as such items would get overwritten when VLC gets updated.
Instead, they should be placed here:
~/Library/Application Support/org.videolan.vlc/lua/extensions
(The ~stands for the user's home directory, and the lua and extensions folders probably need to be created by hand)
Also, the mempos lua program has a few bugs. I'm in the progress of fixing them now.