When trying to go to settings in the BuyNow control, I get the following error.
 
A critical error has occurred.
Object reference not set to an instance of an object.
 
The event viewer has this.
 
Method: DotNetNuke.UI.Containers.ActionButtonList.get_ModuleActions
StackTrace: 
Message:  DotNetNuke.Services.Exceptions.PageLoadException: Object reference not  set to an instance of an object. ---> System.NullReferenceException:  Object reference not set to an instance of an object.    at DotNetNuke.UI.Containers.ActionButtonList.get_ModuleActions()    at DotNetNuke.UI.Containers.ActionButtonList.OnLoad(EventArgs e)    at System.Web.UI.Control.LoadRecursive()    at System.Web.UI.Control.LoadRecursive()    at System.Web.UI.Control.LoadRecursive()    at System.Web.UI.Control.LoadRecursive()    at System.Web.UI.Control.LoadRecursive()    at System.Web.UI.Control.LoadRecursive()    at System.Web.UI.Control.LoadRecursive()    at System.Web.UI.Control.LoadRecursive()    at System.Web.UI.Control.LoadRecursive()    at System.Web.UI.Page.ProcessRequestMain(Boolean  includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)    --- End of inner exception stack trace ---
 
I have tried this on DNN 5.5 locally and 5.4.1 on my prod server.  Both have the same results.