Today on PC #1, itunes cannot access the CDDB server, per the error message. I am advised to check network connections; all diagnostics from itunes are OK. There is some discussion of this on the Apple site and ecoustics. I have downloaded a patch from Gracenote, and reloaded itunes to no avail.
Not fixed yet. About five days for some people - two for me. I did quit itunes, also reloaded the software, ran diagnosis ("all OK") that checks connection to store but not CDDB, and rebooted. No luck.