ICal crashes after 10.4.7

Question

Hey,
I've just applied 10.4.7 combo on this intel iMac, and all my ssh problems disappeared. Which is good But now iCal crashes on opening, after asking for my keychain password. It looks like it's trying to publish but failing, and I can't find where to tell it not to. I've trashed the com.apple.ical.plist (and logged out), held down the shift key, and repaired the Keychain (not that it needed it). Oh, and done all the magic with repairing permissions and fsck - all is fine.
So where do I go from here?
Date/Time: 2006-06-28 15:07:44.404 +1000
OS Version: 10.4.7 (Build 8J2135)
Report Version: 4
Command: iCal
Path: /Applications/iCal.app/Contents/MacOS/iCal
Parent: WindowServer [505]
Version: 2.0.3 (1058)
Build Version: 56
Project Name: iCal
Source Version: 10590000
PID: 607
Thread: 0
Exception: EXCBADACCESS (0x0001)
Codes: KERNINVALIDADDRESS (0x0001) at 0xb1d25560
Thread 0 Crashed:
0 libstdc++.6.dylib 0x90b3952a cxxabiv1::__si_class_type_info::__do_upcast(__cxxabiv1::__class_typeinfo const*, void const*, _cxxabiv1::__class_type_info::__upcastresult&) const + 54
1 libstdc++.6.dylib 0x90b3953e cxxabiv1::__si_class_type_info::__do_upcast(__cxxabiv1::__class_typeinfo const*, void const*, _cxxabiv1::__class_type_info::__upcastresult&) const + 74
2 libstdc++.6.dylib 0x90b390c7 cxxabiv1::__class_type_info::__do_upcast(__cxxabiv1::__class_typeinfo const*, void**) const + 69
3 libstdc++.6.dylib 0x90b38d37 cxxabiv1::__class_type_info::__do_catch(std::typeinfo const*, void**, unsigned) const + 57
4 libstdc++.6.dylib 0x90b37e55 _cxa_getglobals + 351
5 libstdc++.6.dylib 0x90b3853a _gxx_personalityv0 + 658
6 libgcc_s.1.dylib 0x90bcabf7 UnwindRaiseException + 147
7 libstdc++.6.dylib 0x90b38857 _cxathrow + 87
8 com.apple.security 0x911620d7 Security::CssmError::throwMe(long) + 91
9 com.apple.security 0x91160351 Security::CssmClient::ObjectImpl::check(long) + 21
10 com.apple.security 0x9117c47d Security::CssmClient::Decrypt::final(Security::CssmData&) + 65
11 com.apple.security 0x9117ac09 Security::CssmClient::SSGroupImpl::decodeDataBlob(cssm_data const&, cssmaccesscredentials const*, Security::Allocator&, cssm_data&) + 413
12 com.apple.security 0x91165984 Security::CssmClient::SSDbUniqueRecordImpl::get(Security::CssmClient::DbAttribu tes*, Security::CssmDataContainer*, cssmaccesscredentials const*) + 246
13 com.apple.security 0x91166d24 Security::KeychainCore::ItemImpl::getContent(Security::CssmClient::DbAttributes *, Security::CssmDataContainer*) + 238
14 com.apple.security 0x91191fff Security::KeychainCore::ItemImpl::getData(Security::CssmDataContainer&) + 77
15 com.apple.security 0x911a45b9 SecKeychainFindInternetPassword + 805
16 com.apple.calcore 0x99ed59d7 -[CALKeychain loadKeychainInformationsForURL:login:] + 1782
17 com.apple.calcore 0x99ed5ace -[CALKeychain loadKeychainInformationsForURL:] + 105
18 com.apple.calcore 0x99edf253 -[CALURLPublisher(private) loadKeychainInformations] + 109
19 com.apple.calcore 0x99edf85e -[CALURLPublisher setUploadURL:] + 154
20 com.apple.calcore 0x99edaefc -[CALPublisher initWithDictionaryRepresentation:] + 390
21 com.apple.calcore 0x99edf674 -[CALURLPublisher initWithDictionaryRepresentation:] + 57
22 com.apple.calcore 0x99edad54 +[CALPublisher publisherWithDictionaryRepresentation:] + 157
23 com.apple.calcore 0x99ea8782 -[CALNode initWithDictionaryRepresentation:] + 609
24 com.apple.calcore 0x99ea907c -[CALSourceNode initWithDictionaryRepresentation:] + 57
25 com.apple.calcore 0x99ea7b68 +[CALNode nodeWithDictionaryRepresentation:] + 157
26 com.apple.calcore 0x99ea6bcd -[CALCalendarsManager setupWithSourcesPath:withNodesPath:] + 704
27 com.apple.iCal 0x00035a9d 0x1000 + 215709
28 com.apple.iCal 0x00034e9f 0x1000 + 212639
29 com.apple.Foundation 0x92742259 __NSFireMainThreadPerform + 352
30 com.apple.CoreFoundation 0x908565d0 __CFRunLoopPerformPerform + 82
31 com.apple.CoreFoundation 0x90823379 CFRunLoopRunSpecific + 1213
32 com.apple.CoreFoundation 0x90822eb5 CFRunLoopRunInMode + 61
33 com.apple.HIToolbox 0x92f02b90 RunCurrentEventLoopInMode + 285
34 com.apple.HIToolbox 0x92f021ce ReceiveNextEventCommon + 184
35 com.apple.HIToolbox 0x92f020ee BlockUntilNextEventMatchingListInMode + 81
36 com.apple.AppKit 0x933a3771 _DPSNextEvent + 576
37 com.apple.AppKit 0x933a335e -[NSApplication nextEventMatchingMask:untilDate:inMode:dequeue:] + 137
38 com.apple.AppKit 0x9339d0e3 -[NSApplication run] + 512
39 com.apple.AppKit 0x93391037 NSApplicationMain + 573
40 com.apple.iCal 0x00002e57 0x1000 + 7767
41 com.apple.iCal 0x00002cba 0x1000 + 7354
42 com.apple.iCal 0x000c53c1 0x1000 + 803777
Thread 1:
0 libSystem.B.dylib 0x9001aafc select + 12
1 libSystem.B.dylib 0x90024b07 pthreadbody + 84
Thread 2:
0 libSystem.B.dylib 0x9000a5c7 machmsgtrap + 7
1 com.apple.CoreFoundation 0x9082369a CFRunLoopRunSpecific + 2014
2 com.apple.CoreFoundation 0x90822eb5 CFRunLoopRunInMode + 61
3 com.apple.calcore 0x99e6c834 -[CALRunLoopSemaphore down] + 105
4 com.apple.calcore 0x99f03a79 -[CALThreadedOperationHandler run] + 253
5 com.apple.Foundation 0x927291b0 forkThreadForFunction + 123
6 libSystem.B.dylib 0x90024b07 pthreadbody + 84
Thread 0 crashed with i386 Thread State:
eax: 0xb1d25560 ebx: 0x90b3880d ecx:0xbfffe4b0 edx: 0xa119b680
edi: 0x0bed89e0 esi: 0xa119b6c0 ebp:0xbfffe478 esp: 0xbfffe460
ss: 0x0000002f efl: 0x00010297 eip:0x90b3952a cs: 0x00000027
ds: 0x0000002f es: 0x0000002f fs:0x00000000 gs: 0x00000037

Answer 1

I just upgraded my powerbook this afternoon and now all of my ical files are gone, including in the library/application support/ folder. Then isync did it's wonderful automatic thing and the whole thing pretty much got screwed. Is there anyway to revert? .mac and isync is supposed to prevent this right?
G4 PPC Powerbook 1.5 Ghz   Mac OS X (10.4.6)