problem with adding a project to the solution

[sj1187534]

Hi..I am having a problem while trying to add a new project to the exixsting solution in the .NET environment. I set up the IIS's home directory as the folder of the solution too. the error it is throwing is something like this:
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The web server reported the following error when attempting to create or open the web project located at the following URL :
'http://localhost:400/MSI.Web'. 'HTTP/1.1 500 Internal Server Error'.
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The MSI.Web folder is already present in the solutions folder. Can anyone help me with this one.???

Thanks,
SJ