Created Unassigned: Error attempting to Export All [7]

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.Security.Membership.AspNetMembershipProvider.GetPassword(UserInfo user, String passwordAnswer)
at DotNetNuke.Entities.Users.UserController.GetPassword(UserInfo& user, String passwordAnswer)
at forDNN.Modules.UsersExportImport.MainControl.AddPasswordsColumn(DataTable dt)
at forDNN.Modules.UsersExportImport.MainControl.DoExport()
at System.Web.UI.WebControls.LinkButton.RaisePostBackEvent(String eventArgument)
at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
--- End of inner exception stack trace ---