я добавил ASPNET в группу администраторов, теперь выдается другая ошибка...
как расшифровать эти сообщения об ошибках — что там значат цифры с плюсами и номер HttpException?

Server Error in '/QuickStart' Application.
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Access denied to 'd:\Program Files\Microsoft Visual Studio .NET\FrameworkSDK\Samples\QuickStart\' directory. Failed to start monitoring directory changes.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Web.HttpException: Access denied to 'd:\Program Files\Microsoft Visual Studio .NET\FrameworkSDK\Samples\QuickStart\' directory. Failed to start monitoring directory changes.

Source Error:
An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:
[HttpException (0x80004005): Access denied to 'd:\Program Files\Microsoft Visual Studio .NET\FrameworkSDK\Samples\QuickStart\' directory. Failed to start monitoring directory changes.]
System.Web.FileChangesMonitor.StartMonitoringDirectoryRenamesAndBinDirectory(String dir, FileChangeEventHandler callback) +444
System.Web.HttpRuntime.FirstRequestInit(HttpContext context) +324
[HttpException (0x80004005): ASP.NET Initialization Error]
System.Web.HttpRuntime.FirstRequestInit(HttpContext context) +926 System.Web.HttpRuntime.ProcessRequestInternal(HttpWorkerRequest wr) +128
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Version Information: Microsoft .NET Framework Version:1.0.3705.0; ASP.NET Version:1.0.3705.0