After install SP1 MOSS cannot complete configuration wizard step 8 out of 9,
and this message shows up:

Failed to upgrade SharePoint Products and Technologies. An exception of type Microsoft.SharePoint.PostSetupConfiguration.PostSetupConfigurationTaskException was thrown.

Workaround Steps:

1. Stop the services on the server
You can find these in Central Admin/Operations/Services on Server.
You should make a note of the settings for each as you may want them when you restart the services.
This is one place I would have, given the time, determine which of these needed to be stopped.

2. Stop the World Wide Web Publishing service on the server
WWWP is in Windows Services. If you have multiple web front ends I would stop it on all of them
and pay close attention to the instructions for installing SP1 in a farm.

3. Run the upgrade using PSCONFIG
Open a command prompt to the Office Server BIN
(typically 'C:\Program Files\Common Files\Microsoft Shared\web server extensions\12\BIN')

Execute: psconfig -cmd upgrade -inplace b2b -force
NOTE: It did not restart, start the World Wide Web publishing service

4. Restart services in the farm
Go to Central Admin/Operation/Services on Server and restart the services.
It’s recommended to delete the offending database and had Central Admin recreate it.

5. Open the SSP Admin and click on Search Settings under Search
You'll get an error – An Indexer is not assigned to the Shared Services Provider 'YourSSPName'

6. Click on Configure an indexer and a search database for this SSP.
Assign an Index Server, and click OK.