One further thing I forgot to ask about - next time you see this, does anything appear in the console logs while the error dialogs are popping up?
Console.app can be found in the utilities subfolder of your applications folder. Launch it, select "Open Console Log" under the File menu, and then press the "Clear" button on the toolbar. Once you've done that, trigger the error message a couple of times.
If you can paste anything that appears in the window while the alerts are coming up into an email and send it to the
support ninjas, it would be a big help. Thanks!