LightSwitch beta 1: "CreateRuntimeExtensionAssembliesManifest" task failed unexpectedly

Using LightSwitch Beta 1, every time I build my project I get this error on the ServerGenerated project:

The "CreateRuntimeExtensionAssembliesManifest" task failed unexpectedly.
System.NullReferenceException: Object reference not set to an instance of an object.
at Microsoft.LightSwitch.BuildTasks.Extensions.CreateRuntimeExtensionAssembliesManifest.Execute()
at Microsoft.Build.BackEnd.TaskExecutionHost.Microsoft.Build.BackEnd.ITaskExecutionHost.Execute()
at Microsoft.Build.BackEnd.TaskBuilder.ExecuteInstantiatedTask(ITaskExecutionHost taskExecutionHost, TaskLoggingContext taskLoggingContext, TaskHost taskHost, ItemBucket bucket, TaskExecutionMode howToExecuteTask, Boolean& taskResult)

The project was 开发者_C百科building before, and I was publishing using ClickOnce. I tried to publish a new version and it started doing this.