Item has already been added. Key in Dictionary: 'Path'

I reinstalled SQL Server 2008 on my local development machine today. I reinstalled because I could not install the SilverLight development tools on the local machine. I recalled from some earlier issues that SQL Server installed a crippled version of Visual Studio and suspected this to be the problme.

I uninstalled SQL Server 2008, uninstalled Visual Studio and then reinstalled Visual Studio. It worked. Now the SilverLight development extension for VS 2008 install and work correctly

The only problem is that now when I try to reinstall SQL Server 2008, I get the following error message:


TITLE: SQL Server Setup failure.
------------------------------

SQL Server Setup has encountered the following error:

Item has already been added. Key in dictionary: 'path' Key being added: 'path'

Error code 0x84B10001.

------------------------------
BUTTONS:

OK
------------------------------



Any idea what causes this error and how to fix it?
Please don't tell me to uninstall Visual Studio. I have already burned a day on the exercise.

Thanks for you help.

John

.