When I install 2.6a1 onto a Windoze machine I get a dialog:
  There is a problem with this Windows Installer package.
  A program run as part of the setup did not finish as expected.
  Contact your support personnel or package vendor.

Note that it didn't have VS2008 or any other new code installed.
The problem appears related to Tkinter but that isn't clear.

When running the Python console, running
  import Tkinter

results in an error saying that _tkinter can't be loaded.
  DLL load failed.  The system can't find _tkinter.pyd

_tkinter.pyd and tcl84.dll and tk84.dll are in DLLs and
appear to have reasonable permissions.

I suspect something in the install failed to set something
in the registry.

This is on a current-patch XP
system and that I also tried python-2.6.13944.msi
from the buildbot just in case after uninstalling/reinstalling
with no difference.

Attached is a compressed log of the install.

Perhaps this "PROPERTY CHANGE: Deleting SECONDSEQUENCE" 
is the problem?

Here is an excerpt from the log file:


Property(S): Privileged = 1
Property(S): DATABASE = C:\WINDOWS\Installer\5f5ad0.msi
Property(S): OriginalDatabase = C:\cygwin\tmp\python-2.6a1.msi
Property(S): UILevel = 5
Property(S): Preselected = 1
Property(S): CostingComplete = 1
Property(S): OutOfDiskSpace = 0
Property(S): OutOfNoRbDiskSpace = 0
Property(S): PrimaryVolumeSpaceAvailable = 0
Property(S): PrimaryVolumeSpaceRequired = 0
Property(S): PrimaryVolumeSpaceRemaining = 0
Property(S): SOURCEDIR = C:\cygwin\tmp\
Property(S): SourcedirProduct = {0BA82E1B-52FD-4E03-8610-A6C76238E8A8}
Property(S): ProductToBeRegistered = 1
MSI (s) (FC:D0) [16:38:30:939]: MainEngineThread is returning 1603
MSI (s) (FC:C0) [16:38:30:939]: Destroying RemoteAPI object.
MSI (s) (FC:54) [16:38:30:939]: Custom Action Manager thread ending.
MSI (c) (E0:54) [16:38:30:954]: Back from server. Return value: 1603
MSI (c) (E0:54) [16:38:30:954]: Decrementing counter to disable 
shutdown. If counter >= 0, shutdown will be denied.  Counter after 
decrement: -1
MSI (c) (E0:54) [16:38:30:954]: PROPERTY CHANGE: Deleting SECONDSEQUENCE 
property. Its current value is '1'.
Action ended 16:38:30: ExecuteAction. Return value 3.
MSI (c) (E0:54) [16:38:30:954]: Doing action: FatalError
Action 16:38:30: FatalError.
Action start 16:38:30: FatalError.
Action 16:38:30: FatalError. Dialog created
Action ended 16:38:32: FatalError. Return value 2.
Action ended 16:38:32: INSTALL. Return value 3.
MSI (c) (E0:54) [16:38:32:375]: Destroying RemoteAPI object.
MSI (c) (E0:2C) [16:38:32:375]: Custom Action Manager thread ending.
Property(C): X = C:\Python26\Tools\pynche\X\
Property(C): UpgradeCode = {65E6DE48-A358-434D-AA4F-4AF72DB4718F}
Property(C): ProductName = Python 2.6a1
Property(C): ProductCode = {0BA82E1B-52FD-4E03-8610-A6C76238E8A8}
Property(C): ProductVersion = 2.6.101
Property(C): Manufacturer = Python Software Foundation