This is super old, but for any who encounter this problem in the future, you may need to check your 'cue ' and 'list' chunks. Many resources online don't match up to what Wwise is looking for - although the 1994 multimedia standards update doc from Microsoft seems to match up with it pretty well, and is the most official-looking WAVE standard I've come across. To make WWise happy, contrary to what most websites say but totally in line with the Microsoft standard, for each of your cue points you must provide a Position regardless of whether there is a 'plst' and use a ChunkID of 'LIST' instead of 'list' for your associated data list.
I don't think I've run across any websites or info that match up with this, except for that ancient pdf.