Hello guys i have error on my SQL 2008 r2 express set up the error is like this :

TITLE: SQL Server Setup failure.
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SQL Server Setup has encountered the following error:

Object of type 'Microsoft.SQL.Chainer.Package.PropertiesTypeProperty' cannot be converted to type 'Microsoft.SQL.Chainer.Package.PropertiesTypeProperty'..

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BUTTONS:

OK
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please help me