Merge? Replace? Again? Weird .Mac Problem Du Jour

I’m stumped.

I have removed this computer from the .Mac system preferences pane, added it back. I told it to reset my information. Every time this workstation goes to .Mac to perform a sync, it asks me about my calendars. These same calendars sync to two other Macs via .Mac without incident.
There is nothing in dotmacsync.log that mentions the calendars.

2006-02-16 10:12:52 -0500|Info|Starting .Mac Sync Session for 'sempai'
2006-02-16 10:13:01 -0500|Info|The dataclass Keychains will not sync because the dataclass is disabled in the .Mac Preferences
2006-02-16 10:13:01 -0500|Info|No anchors or first sync for this dataclass - Full Syncing dataclass Mail Rules, Signatures, and Smart Mailboxes
2006-02-16 10:13:01 -0500|Info|The dataclass Mail Rules, Signatures, and Smart Mailboxes will not sync because it is not enabled in the .Mac Sync Preferences
2006-02-16 10:13:01 -0500|Info|No anchors or first sync for this dataclass - Full Syncing dataclass Mail Accounts
2006-02-16 10:13:01 -0500|Info|The dataclass Mail Accounts will not sync because it is not enabled in the .Mac Sync Preferences
2006-02-16 10:13:01 -0500|Info|Nothing to sync for this session - cancelling the sync
2006-02-16 10:13:01 -0500|Info|Ended .Mac Sync Session

Any ideas? Remember, I have removed this machine, added it back, done a reset, to no avail. I even did a “Backup” from iCal and AddressBook on known-good machines, then imported that backup to iCal and AddressBook on this machine. Still asks me to merge or replace.