Hi

I am setting up a demo site and having some issues with episerver langues add-on. 

Installed new Episerver web site project  "alloy mvc" from Visual studio.  I run the site and enables one extra language and enables new language in edit mode.

PM> Install-Package EPiServer.Labs.LanguageManager
Attempting to resolve dependency 'EPiServer.Packaging (≥ 3.2.0 && < 4.0)'.
Attempting to resolve dependency 'EPiServer.Framework (≥ 7.15.0 && < 8.0)'.
Attempting to resolve dependency 'Newtonsoft.Json (≥ 5.0.8 && < 7.0)'.
Attempting to resolve dependency 'Microsoft.AspNet.Mvc (≥ 4.0.20710.0 && < 6.0)'.
Attempting to resolve dependency 'Microsoft.AspNet.WebPages (≥ 3.2.2 && < 3.3.0)'.
Attempting to resolve dependency 'Microsoft.Web.Infrastructure (≥ 1.0.0.0)'.
Attempting to resolve dependency 'Microsoft.AspNet.Razor (≥ 3.2.2 && < 3.3.0)'.
Attempting to resolve dependency 'structuremap (≥ 2.6.4.1 && < 3.0)'.
Attempting to resolve dependency 'Nuget.Core (≥ 2.5 && < 2.8)'.
Attempting to resolve dependency 'EPiServer.CMS.Core (≥ 7.5 && < 8.0)'.
Attempting to resolve dependency 'EPiServer.Logging.Log4Net (< 2.0)'.
Attempting to resolve dependency 'log4net (= 1.2.10)'.
Attempting to resolve dependency 'Castle.Windsor (≥ 3.2 && < 4.0)'.
Attempting to resolve dependency 'Castle.Core (≥ 3.2.0)'.
Attempting to resolve dependency 'EPiServer.CMS.UI (≥ 7.5 && < 8.0)'.
Attempting to resolve dependency 'EPiServer.CMS.UI.Core (= 7.17.0)'.
Attempting to resolve dependency 'DotNetZip (= 1.9.1.8)'.
Installing 'EPiServer.Labs.LanguageManager 1.1.1.7514'.
Successfully installed 'EPiServer.Labs.LanguageManager 1.1.1.7514'.
Adding 'EPiServer.Labs.LanguageManager 1.1.1.7514' to Demo2.
Successfully added 'EPiServer.Labs.LanguageManager 1.1.1.7514' to Demo2.

When i add the languages gadget i get this error (and languages gadgets is emty). It is possible to translate pages but the gadget is not working.

I have also tried installing add-on from store. Also tried updating all episerver nugets.

http://localhost:52901/EPiServer/EPiServer.Labs.LanguageManager/Stores/language/null Failed to load resource: the server responded with a status of 500 (Internal Server Error)
dojo.js:15 _317: Unable to load /EPiServer/EPiServer.Labs.LanguageManager/Stores/language/null status: 500
http://localhost:52901/EPiServer/EPiServer.Labs.LanguageManager/Stores/language/null Failed to load resource: the server responded with a status of 500 (Internal Server Error)
dojo.js:15 _317: Unable to load /EPiServer/EPiServer.Labs.LanguageManager/Stores/language/null status: 500message: "Unable to load /EPiServer/EPiServer.Labs.LanguageManager/Stores/language/null status: 500"response: ObjectresponseText: "
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Server Error in '/' Application.

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 Unable to cast object of type 'System.Web.Security.RolePrincipal' to type 'EPiServer.Security.VirtualRolePrincipal'. 
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↵             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.
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↵             Exception Details: System.InvalidCastException: Unable to cast object of type 'System.Web.Security.RolePrincipal' to type 'EPiServer.Security.VirtualRolePrincipal'.


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↵            Source Error: 


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↵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.
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↵            Stack Trace: 


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↵[InvalidCastException: Unable to cast object of type 'System.Web.Security.RolePrincipal' to type 'EPiServer.Security.VirtualRolePrincipal'.]
↵   EPiServer.Labs.LanguageManager.Controllers.LanguageStore.IsCurrentUserInAdminRole() +36
↵   lambda_method(Closure , ControllerBase , Object[] ) +62
↵   System.Web.Mvc.ActionMethodDispatcher.Execute(ControllerBase controller, Object[] parameters) +14
↵   System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext controllerContext, IDictionary`2 parameters) +157
↵   System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary`2 parameters) +27
↵   System.Web.Mvc.<>c__DisplayClass15.b__12() +56
↵   System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodFilter(IActionFilter filter, ActionExecutingContext preContext, Func`1 continuation) +256
↵   System.Web.Mvc.<>c__DisplayClass17.b__14() +22
↵   System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodFilter(IActionFilter filter, ActionExecutingContext preContext, Func`1 continuation) +256
↵   System.Web.Mvc.<>c__DisplayClass17.b__14() +22
↵   System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodWithFilters(ControllerContext controllerContext, IList`1 filters, ActionDescriptor actionDescriptor, IDictionary`2 parameters) +190
↵   System.Web.Mvc.ControllerActionInvoker.InvokeAction(ControllerContext controllerContext, String actionName) +522
↵   EPiServer.Shell.Services.Rest.RestControllerBase.ExecuteCore() +175
↵   System.Web.Mvc.ControllerBase.Execute(RequestContext requestContext) +181
↵   System.Web.Mvc.ControllerBase.System.Web.Mvc.IController.Execute(RequestContext requestContext) +10
↵   EPiServer.Shell.Services.Rest.RestHttpHandler.ProcessRequest(HttpContextBase httpContext) +197
↵   EPiServer.Shell.Services.Rest.RestHttpHandler.ProcessRequest(HttpContext context) +42
↵   System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +341
↵   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +69
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↵            Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.5.22.0
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↵"stack: (...)get stack: function () { [native code] }set stack: function () { [native code] }status: 500xhr: XMLHttpRequest__proto__: TMPdojo.js:15 _498dojo.js:15 (anonymous function)dojo.js:15 _2cddojo.js:15 _2cbdojo.js:15 reject.errbackdojo.js:15 _2cddojo.js:15 _2cbdojo.js:15 reject.errbackdojo.js:15 (anonymous function)dojo.js:15 _2f2dojo.js:15 _2ecdojo.js:15 _30a.rejectdojo.js:15 _2f8dojo.js:15 _2f2dojo.js:15 _2ecdojo.js:15 _30a.rejectdojo.js:15 _2f8dojo.js:15 _2f2dojo.js:15 _2ecdojo.js:15 _30a.rejectdojo.js:15 _2f8dojo.js:15 _2f2dojo.js:15 _2ecdojo.js:15 _30a.rejectdojo.js:15 _2f8dojo.js:15 _2f2dojo.js:15 _2ecdojo.js:15 _30a.rejectdojo.js:15 _4f2dojo.js:15 _4fe
:55930/e635aa06cd254720b61b01108f3d4369/browserLink:37 Setting 'XMLHttpRequest.withCredentials' for synchronous requests is deprecated.