I would repair file permissions on the root drive, and see if that gets it. These sometimes get munged up during an update.

Have you tried Hayne's list of standard troubleshooting suggestions? See links in Post 5 of this thread.

In particular disable any 3rd party applications that you may have while trying to troubleshoot - one of them they may be responsible, but if not it is hard for others here to help unless your system matches their's as much as possible.

Also looking at (or if you like, attaching, to a post here, parts of) your system log may give you a clue as to what's going on.

iTunes Not Responding - possible fix?
 

I found this out on the Apple discussion boards. Looks like there is some incompatibility between iTunes, Apple update 10.3.9, Quicktime 7 and ProTools. For me, I simply unplugged my MBox converter and iTunes started just fine - no need to delete prefs, recreate library or anything. Something to do with core audio files from Digidesign? I'm a novice but I thought you might find this useful. My symptoms were very similar to all those noted here - "all of a sudden" iTunes fails to start, spins the beach ball, and requires a Force Quit. I've no idea how to fix this permanently but at least I reassured myself that my Mac itself hasn't gone haywire.

Hope this helps:
http://discussions.info.apple.com/we...DY.0@.68addf52

Sounds like a third party problem that will have to be resolved by the developer. Best thing you can do is give the developer some feedback. The more feedback the sooner they are likely to find the problem with their software.

the Mbox unplugging thing works, and (I don't use it for sound output) iTunes runs fine if I plug it in after launch. Thanks for the link - am studying it at the moment....

Problem resolved elsewhere
 

Someone more recently posted that if you go into the Digidesign core audio set up and remove iTunes from the list of supported applications everything is hunky dorey again. Seems to be the case...

Resolved my problem
 

I was receiving the the "Connection Failed" error message in iTunes followed by a can not find a.gif and b.gif message. I did the move "iTunes 4 Music Library" and .xml files but the same error occured on the import.

I found that a.gif and b.gif is referrenced in a few .mov files in my "Unknown Artist/Unknown Album" directory using the strings Unix command. I moved these files out and the problem went away.

I received the same "Connection Failed" error when I attempt to load the .mov files in QuickTime. I guess the new QuickTime does not properly handle unknown references too well.

The references in the .mov files have the form:
#Macintosh HD:API Docs:Effects:b.gif

FWIW, I do not know where the bad files came from. It looks like they may have come from a directory scan for music or movie files.

I hope this helps.