WA 5.5 crashing on many m4a's

[sebt]

Previous WA versions ie. 5.2x 5.3x played these files just fine, but I have at least 2 albums as m4a files (aac wrapped in mp4 container) that immediately crash winamp when I try to play them. One of these albums was originally ripped with winamp 5.2x.

Interestingly, if I *don't* hit "Don't send", WA will play the track all the way to the end even though I have a crash-dialog to action.

I can make an "offending" m4a available if it helps to nail this bug.

nb. I have installed the mp3 patch which has made no difference.

- Tried clean install
- no extra plugins installed
- Problem seen on these machines:
1. Core2 Duo E6750, Gigabyte GA-P35-DQ6 mobo, 2M RAM, XP SP2, RME Fireface 400 latest f/w, drivers
2. IBM Thinkpad T43, 1.5G RAM, Centrino 2Ghz, XP SP1, onboard audio (Realtek afaik)

thx, sebt