There is a serious bug with VLC and converting a flv file to a wav file. Using the default convert options, select an flv file and choose the "Audio - Wav CD Quality" profile type. The converter immediately fails and no file is made.
This function works properly in VLC version 1.0.5 but is broken in each version since. Reverting to version 1.0.5 proves that this function still works, while upgrading to later versions (1.1.11) proves it broken.
A second bug exists in the VLC Convert interface. The mnemonic for the Convert's "Open Media" Convert and Cancel buttons are the same ('C'):
Convert/Save Cancel
This means when you try and use the "Alt + C" shortcut, neither button is activated.
I suggest removing the 'C' mnemonic on the Cancel button and relying on the "Esc" button to cancel the dialog, or using the 'v' as the Convert mnemonic.