Palm has issued a fix for an issue where the Treo 750 smartphone can stop playing sounds for incoming calls and reminders. The root cause of the Treo 750 losing Audio Alert capabilities is too many applications utilizing the audio driver. In certain situations when the user activates too many applications that need to share the device audio driver, system sounds and notification sounds can become muted. These applications can include the device Notes Recorder, the Vibrate Motor, Voice Command, Windows Media Player, and/or the camera/video recorder.
The Audio Alerts Update will ensure that all system sounds remain audible.
The patch is not a ROM update so if you perform a hard reset later, you will need to reapply the patch. Before trying to install it, also check that you need it; it looks like only Cingular and AT&T Treos require it.
The Update can also be downloaded via OTA.