IOFireWireSBP2Login::fetchAgentWriteComplete fetch agent write failed! retryingIt would repeat five or six times, then pause about a minute, and then repeat again, etc. Sometimes it would appear within the first minute after boot and other times it would take 30-40 minutes until it would appear - the same frequency the problems would develop when booted to the Finder. Suspecting a bad FW port (the lower port on the motherboard), I swapped the FW devices to the upper port...and the problem disappeared.
Bottom line: Bad FireWire port. Still under warranty, I brought the unit into CompUSA. The Apple technician could not find the problem using whatever standard procedures Apple has developed. (Most burns to a FW device will succeed.) However, when I provided a photo of the screen showing the "IOFireWireSBP2Login...etc." and explained how I diagnosed the problem, the tech agreed that the motherboard would need to be replaced. So, if you have this problem, take a picture of the screen to document it and don't be too hard on the tech because this kind of a problem is apparently not documented very well for them.
PS - I'm buying AppleCare before the warranty is up!

