I just bought Umbraco Pro for Courier but can't get it to work in our new medium trust environments.

I have installed it on both instances, the destination server is on .net 3.5 running umbraco 4.5.2 in medium trust. I have evn tried the .Net 4 build, but i get the same error:

Transfer Error! 
Details: 

System.Web.Services.Protocols.SoapException: System.Web.Services.Protocols.SoapException: Server was unable to process request. ---> System.TypeInitializationException: The type initializer for 'Umbraco.Courier.BusinessLogic.Dependencies.MessengerDependencyFactory' threw an exception. ---> System.Security.SecurityException: Request for the permission of type 'System.Security.Permissions.FileIOPermission, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' failed. at System.Security.CodeAccessSecurityEngine.Check(Object demand, StackCrawlMark& stackMark, Boolean isPermSet) at System.Security.CodeAccessSecurityEngine.Check(CodeAccessPermission cap, StackCrawlMark& stackMark) at System.Security.CodeAccessPermission.Demand() at System.AppDomainSetup.VerifyDir(String dir, Boolean normalize) at Umbraco.Courier.BusinessLogic.Helpers.TypeResolver.GetAssignablesFromType[T](String[] files) at Umbraco.Courier.BusinessLogic.Helpers.TypeResolver.GetAssignablesFromType[T](String path, String filePattern) at Umbraco.Courier.BusinessLogic.Helpers.TypeFinder.FindClassesOfType[T](Boolean useSeperateAppDomain) at Umbraco.Courier.BusinessLogic.Dependencies.MessengerDependencyFactory.Initialize() at Umbraco.Courier.BusinessLogic.Dependencies.MessengerDependencyFactory..cctor() --- End of inner exception stack trace --- at Umbraco.Courier.BusinessLogic.Dependencies.MessengerDependencyFactory.MessengerDependency(String key) at Umbraco.Courier.Webservices.Messenger.ValidateDependency(String dependencyKey, Object validationObject, String login, String password) --- End of inner exception stack trace --- at System.Web.Services.Protocols.SoapHttpClientProtocol.ReadResponse(SoapClientMessage message, WebResponse response, Stream responseStream, Boolean asyncCall) at System.Web.Services.Protocols.SoapHttpClientProtocol.Invoke(String methodName, Object[] parameters) at Umbraco.Courier.CourierMessengerService.Messenger.ValidateDependency(String dependencyKey, Object validationObject, String login, String password) at Umbraco.Courier.BusinessLogic.Proxy.Messenger.ValidateDependency(String dependencyKey, Object validationObject, String& errorMessage, String login, String password) at Umbraco.Courier.BusinessLogic.Messengers.Helpers.MessengerHelper.ValidateDependencies(User u, Object objectToValidate, List`1 dependencies, String errorMessageTemplate, String& errorMessage) at Umbraco.Courier.BusinessLogic.Messengers.Content.ContentMessenger.Validate(Object id, Object parentId, String& errorMessage, User u) at Umbraco.Courier.Dialogs.TransferNode.validateNode(Int32 selectedId, Boolean transferChildren, String& validationErrors) at Umbraco.Courier.Dialogs.TransferNode.Page_Load(Object sender, EventArgs e) 

Mike