System.InvalidCastException

When I build my application, I get the following message:

Warning 7 Failed: System.InvalidCastException: Specified cast is not valid.
at „..(IEnumerable`1 )
at „..( methodBody, & blockData, IDictionary`2 instructionIndexToIlOffsetMap)
at „..( , Dictionary`2 )
at ..()
at ..()
at ..( , FileInfo , IAssemblyWriterOptions )
at ..()
at SmartAssembly.ConsoleApp.OnProcessingFeedback(Object , )
at System.EventHandler`1.Invoke(Object sender, TEventArgs e)
at ..[](EventHandler`1 , )
at ..(ProjectProcessingStep , Exception )
at ..()
at SmartAssembly.ConsoleApp.PerformBuild(String , , Dictionary`2 )
at SmartAssembly.ConsoleApp.PerformProjectAction(String , , Todo , Dictionary`2 )
at SmartAssembly.ConsoleApp.CommandLineAction(String , Todo , Dictionary`2 )
at SmartAssembly.ConsoleApp.Run(String[] )

This is then followed by:

Error 6 SmartAssembly build failed:
Failed: System.InvalidCastException: Specified cast is not valid.
at „..(IEnumerable`1 )
at „..( methodBody, & blockData, IDictionary`2 instructionIndexToIlOffsetMap)
at „..( , Dictionary`2 )
at ..()
at ..()
at ..( , FileInfo , IAssemblyWriterOptions )
at ..()


Both exceptions show up in column 5, line 144 of project.csproj