Hem, sorry, I posted previous reply a bit too hastily,
The issue is fixed when I use VLC 1.1.2 as "admin", but not as normal user. The settings are the default one in both cases.
I encounter a similar issue with VLC 1.1.0.
I tried playing downloaded .flv videos, but soundtrack plays twice like an echo, although video is OK.
The same files plays OK on GOM Player 2.1.26.
Is that a settings issue ?