Here is the installer log from the last failure (MacBook Pro 2.33 GHz Intel Core 2 Duo (Late 2006), BC 2.0 installation, changed Language to 1033, Installed ATI graphics driver update from
http://ati.amd.com/support/drivers/mac/bootcamp-xp.html, uninstalled InputRemapper):
MSI (c) (B0:04) [13:13:41:871]: Doing action: GetIntelGRXID
Action 13:13:41: GetIntelGRXID.
Action start 13:13:41: GetIntelGRXID.
MSI (c) (B0:04) [13:13:41:871]: Transforming table CustomAction.
MSI (c) (B0:04) [13:13:41:887]: Transforming table CustomAction.
MSI (c) (B0:04) [13:13:41:887]: Note: 1: 2262 2: CustomAction 3: -2147287038
MSI (c) (B0:04) [13:13:41:887]: Transforming table Binary.
MSI (c) (B0:04) [13:13:41:887]: Transforming table Binary.
MSI (c) (B0:04) [13:13:41:887]: Note: 1: 2262 2: Binary 3: -2147287038
MSI (c) (B0:7C) [13:13:41:887]: Invoking remote custom action. DLL: C:\DOKUME~1\bkuemmer\LOKALE~1\Temp\MSI374.tmp, Entrypoint: GetDeviceId
Enum hardwareIDs for Intel Graphics 965
Starting loop through Device Info list
Action ended 13:13:42: GetIntelGRXID. Return value 3.
MSI (c) (B0:04) [13:13:42:090]: Doing action: SetupCompleteError
Action 13:13:42: SetupCompleteError.
Action start 13:13:42: SetupCompleteError.
It seems that the installer fails when it tries to find out something about Intel Graphics hardware, the funny thing is that the MacBook Pro does have an ATI Radeon X1600). Very strange...
I still think this could have something to do with the ATI graphics driver update which is "official", but I can not find a way to uninstall it...