Update, if you can, to 12.3(4)JA or downgrade to 12.2(15)XR2.
12.3(2) Had some pretty ugly issues, depending on what radios you have and what features (and encryption, and auth, and .....) are selected.
12.3(4) appears to be much more stable. I haven't had any issues since I updated (from 12.3.2 ... and before that 12.2(15)XR2).
It's been running a couple months now with no problems (AP1220 w/ radio upgrade to the '21 G radio).
Good Luck
Scott