The nice thing about Google is that if you have a tech support problem, you can copy and paste the error and find 10 other people who had the problem. Perfect example is the worst debug message in recent memory, AOL's: feedbag error.
It's a Friday afternoon before a three day weekend so my employer is paying me to mod my desktop with some Unsanity and Panic software while I do my weekly server upgrades.
I just rebooted after some fairly big tweaks, including upgrading to 10.3.4, and I get the error I pasted in my title bar. Related to the Unsanity/Panic stuff? Doubtful. This is the Mail.app, which hasn't been touched. The 10.3.4 upgrade is probably more likely. I just can't seem to find anyone with answers in Google.
Which is why I'm posting. Maybe someone can figure it out. Maybe I'll figure it out and update here. Maybe I shouldn't rely on Google for tech support. Ah well..My dock is SEE-THRU!