Symptoms
You put the Microsoft SQL Server 2008 setup binary files in a folder whose path is in the 8.3 compatible format. When you start the Setup program, an exception may occur and the Setup program fails during the LoadExtensions action. Additionally, thefollowing error message is logged in the Detail_GlobalRules.txt file in the setup log folder:

<Date><Time> Slp:Message:
<Date><Time> Slp:Object of type ‘Microsoft.SQL.Chainer.Package.PropertiesTypeProperty’ cannot be converted to type ‘Microsoft.SQL.Chainer.Package.PropertiesTypeProperty’.
<Date><Time> Slp:Stack:
<Date><Time> Slp:at System.RuntimeType.CheckValue(Object value, Binder binder, CultureInfo culture, BindingFlags invokeAttr)
<Date><Time> Slp:at System.Reflection.MethodBase.CheckArguments(Object[] parameters, Binder binder, BindingFlags invokeAttr, CultureInfo culture, Signature sig)
<Date><Time> Slp:at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture, Boolean skipVisibilityChecks)
<Date><Time> Slp:at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
<Date><Time> Slp:at Microsoft.SqlServer.Setup.Chainer.Workflow.ActionDatastoreIntegration.SetPropertiesOnRunningAction(ActionKey key, TextWriter loggingStream)
<Date><Time> Slp:at Microsoft.SqlServer.Setup.Chainer.Workflow.ActionMetadata.NotifyInExecution(ActionKey actionRunning, TextWriter loggingStream)
<Date><Time> Slp:at Microsoft.SqlServer.Setup.Chainer.Workflow.ActionInvocation.InvokeAction(WorkflowObject metabase, TextWriter statusStream)
<Date><Time> Slp:at Microsoft.SqlServer.Setup.Chainer.Workflow.PendingActions.InvokeActions(WorkflowObject metaDb, TextWriter loggingStream)
Note The 8.3 compatible format refers to the 8 characters that are used for the file name, and the 3 characters that are used for the file name extension. This format is used for MS-DOS. For example, the file name “ABCDEFGHIJK” in the 8.3 compatible format is “ABCDEF~1.”
Resolution
When SQL Server 2008 uses the Assembly.LoadFrom() function to load file name extensions, the 8.3 compatible path cannot match the real path, and this causes the exception that is described in the “Symptoms” section.