Mac Help crashing OS 10.5.5

Hi all, it's a puzzle this one. I'm trying to access help on iCal sharing on MobileMe. iCal pointed me at Mac Help accessed through Finder.

When I click on Mac Help, the programme (only, not my computer) crashes with this: (I tried to copy the summary but it wouldn't copy)

Anyone recognise something that I can do anything about?

Process: Help Viewer [199]
Path: /System/Library/CoreServices/Help Viewer.app/Contents/MacOS/Help Viewer
Identifier: com.apple.helpviewer
Version: 4.0.1 (170.3)
Build Info: HelpViewer-1700300~5
Code Type: X86 (Native)
Parent Process: launchd [112]

Date/Time: 2008-09-19 11:00:33.613 +0100
OS Version: Mac OS X 10.5.5 (9F33)
Report Version: 6

Exception Type: EXC_CRASH (SIGABRT)
Exception Codes: 0x0000000000000000, 0x0000000000000000
Crashed Thread: 0

Thread 0 Crashed:
0 libSystem.B.dylib 0x93ea0b9e __kill + 10
1 libSystem.B.dylib 0x93f17ec2 raise + 26
2 libSystem.B.dylib 0x93f2747f abort + 73
3 libstdc++.6.dylib 0x95716005 0x956ce000 + 294917
4 libstdc++.6.dylib 0x9571410c __gxx_personality_v0 + 1108
5 libstdc++.6.dylib 0x9571414b std::terminate() + 29
6 libstdc++.6.dylib 0x95714261 __cxa_throw + 101
7 com.apple.helpui 0x001219f6 _IAAssertionFunc(char const*, int, char const*, char const*, long) + 152

Thread 1:
0 libSystem.B.dylib 0x93e324a6 mach_msg_trap + 10
1 libSystem.B.dylib 0x93e39c9c mach_msg + 72
2 com.apple.CoreFoundation 0x96c770ce CFRunLoopRunSpecific + 1790
3 com.apple.CoreFoundation 0x96c77cf8 CFRunLoopRunInMode + 88
4 com.apple.CFNetwork 0x96d43eca CFURLCacheWorkerThread(void*) + 396
5 libSystem.B.dylib 0x93e636f5 _pthread_start + 321
6 libSystem.B.dylib 0x93e635b2 thread_start + 34

Thread 0 crashed with X86 Thread State (32-bit):
eax: 0x00000000 ebx: 0x93f2743f ecx: 0xbfffdf5c edx: 0x93ea0b9e
edi: 0x00164cfa esi: 0xa0434578 ebp: 0xbfffdf78 esp: 0xbfffdf5c
ss: 0x0000001f efl: 0x00000286 eip: 0x93ea0b9e cs: 0x00000007
ds: 0x0000001f es: 0x0000001f fs: 0x00000000 gs: 0x00000037
cr2: 0xa0627108

Binary Images:
0x1000 - 0xaffc com.apple.helpviewer 4.0.1 (170.3) <da2989571195cfbde6c479294ff69e60> /System/Library/CoreServices/Help Viewer.app/Contents/MacOS/Help Viewer

Tried to add the screen grab but don't know how to do that either . . .

Wish I could help, but I tried what you did today and it worked fine. I just updated to OS 10.5.5 two days ago.

Thanks Tarek - that tells me it's probably specific to my machine. I repaired all my permissions just in case but no joy.

I might just have to wait and see what happens.

I appreciate you looking.