IIS: erro "Could not load type"

[999ANDRE999]

Vivam pessoal,

Tenho um servidor a rodar o windows server 2008 R2 standard e necessito de colocar uma aplicação web .net online através do IIS.

Fiz a compilação do projeto em visual studio 2010 usando o "Publish web site".

coloco as pastas e ficheiros que são gerados da compilação no servidor e quando faço o browse aparece a seguinte tela e nada funciona:

Server Error in '/' Application.

Could not load type 'System.Reflection.CustomAttributeExtensions' from assembly 'mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'.

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.TypeLoadException: Could not load type 'System.Reflection.CustomAttributeExtensions' from assembly 'mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'.

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:

[TypeLoadException: Could not load type 'System.Reflection.CustomAttributeExtensions' from assembly 'mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'.]

Npgsql.NpgsqlConnectionStringBuilder.<.cctor>b__3(PropertyInfo p) in d:\pginstaller.auto\Npgsql.windows\src\Npgsql\NpgsqlConnectionStringBuilder.cs:102

System.Linq.WhereArrayIterator`1.MoveNext() +43

System.Linq.Buffer`1..ctor(IEnumerable`1 source) +488

System.Linq.Enumerable.ToArray(IEnumerable`1 source) +104

Npgsql.NpgsqlConnectionStringBuilder..cctor() in d:\pginstaller.auto\Npgsql.windows\src\Npgsql\NpgsqlConnectionStringBuilder.cs:100

[TypeInitializationException: The type initializer for 'Npgsql.NpgsqlConnectionStringBuilder' threw an exception.]

Npgsql.NpgsqlConnectionStringBuilder..ctor(String connectionString) in d:\pginstaller.auto\Npgsql.windows\src\Npgsql\NpgsqlConnectionStringBuilder.cs:84

Npgsql.NpgsqlConnection.set_ConnectionString(String value) in d:\pginstaller.auto\Npgsql.windows\src\Npgsql\NpgsqlConnection.cs:246

Npgsql.NpgsqlConnection..ctor(String connectionString) in d:\pginstaller.auto\Npgsql.windows\src\Npgsql\NpgsqlConnection.cs:142

DataBase.Conecta() +63

SiteMaster.AddUsertoDB() +16

SiteMaster.Page_Load(Object sender, EventArgs e) +247

System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e) +25

System.Web.UI.Control.LoadRecursive() +71

System.Web.UI.Control.LoadRecursive() +190

System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +3064

Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.0.30319.1031

Alguem me consegue ajudar em relação a este assunto?

[Rui Carlos]

Experimenta correr isso numa versão mais recente do Windows Server/IIS/.Net.