Error Loading Block: RSVP Entry Show Details

C:\inetpub\wwwroot\Plugins\rocks_pillars\ServiceReservation\ReservationEntry.ascx.cs(466): error CS0117: 'CommonMergeFieldsOptions' does not contain a definition for 'GetLegacyGlobalMergeFields'

   at System.Web.Compilation.BuildManager.CompileWebFile(VirtualPath virtualPath)
   at System.Web.Compilation.BuildManager.GetVPathBuildResultInternal(VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile, Boolean throwIfNotFound, Boolean ensureIsUpToDate)
   at System.Web.Compilation.BuildManager.GetVPathBuildResultWithNoAssert(HttpContext context, VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile, Boolean throwIfNotFound, Boolean ensureIsUpToDate)
   at System.Web.Compilation.BuildManager.GetVPathBuildResult(HttpContext context, VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile, Boolean ensureIsUpToDate)
   at System.Web.UI.TemplateControl.LoadControl(VirtualPath virtualPath)
   at Rock.Web.UI.RockPage.OnInit(EventArgs e) in \\Rock\Web\UI\RockPage.cs:line 1391