Webmatrix Joomla Installation Fail

Hi Guys,

I recently made the switch to IIS and do most of my development on PHP and Joomla.

When i try to install Joomla from webmatrix gallery and select mssql, even before it can download the package it always fails with the below error. If i use mysql it works well.

 Please tell me how i can rectify this problem. I have also installed drivers 3.0 for ms sql for php 5.3.

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Microsoft Web Application Gallery
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There was an error resuming the installation.

Object reference not set to an instance of an object.
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OK
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System.NullReferenceException: Object reference not set to an instance of an object.
   at Microsoft.Web.PlatformInstaller.InstallManager.SortInstallers(IEnumerable`1 installers)
   at Microsoft.Web.PlatformInstaller.InstallManager.Load(IEnumerable`1 installers)
   at Microsoft.WebMatrix.Gallery.WebMatrixInstallerService.LoadProducts(List`1 itemsToInstall)
   at Microsoft.WebMatrix.Gallery.WPF.ProgressPage.<>c__DisplayClass14.<>c__DisplayClass18.<StartProductInstall>b__e()
   at Microsoft.WebMatrix.Gallery.EventHandlerSynchronization.WaitForInvocationWhileExecuting[T](EventProxy`1 target, Action callback)
   at Microsoft.WebMatrix.Gallery.WPF.ProgressPage.<>c__DisplayClass14.<StartProductInstall>b__d(Object threadState)
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Download LOG

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DownloadManager Information: 0 : Adding product 'Joomla' to the cart
DownloadManager Error: 0 : Object reference not set to an instance of an object.
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 Thank You