Error at Import MAME Arcade Full Set Wizard screen

[Cloudster]

I keep getting this error whenever it opens up the 'Import MAME Arcade Full Set Wizard' window.

App:     LaunchBox
Version: 13.16
Theme:   Default
Type:    System.NullReferenceException
Site:    Void QueryTransformerThread()
Source:  LaunchBox

   at Unbroken.LaunchBox.Windows.Desktop.ViewModels.MameFullSetWizardRomLocationViewModel.QueryTransformerThread()
   at Unbroken.LaunchBox.Windows.Threading.<>c__DisplayClass0_0.ConcatConcreteClient()
   at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state)
--- End of stack trace from previous location ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()

Recent Log:

   2:49:16 PM Exception

 

[Cloudster]

Any ideas?