Compiler Error Message: CS0246: The type or namespace name 'CMSModules_PortalEngine_Controls_WebParts_WebPartZoneProperties' could not be found (are you missing a using directive or an assembly reference?)

Source File: c:\inetpub\wwwroot\CMSModules\PortalEngine\UI\WebParts\WebPartZoneProperties.aspx.cs Line: 128

Line 126: if (!isVariantTab)
Line 127: {
Line 128: CMSModules_PortalEngine_Controls_WebParts_WebPartZoneProperties webPartZonePropertiesElem = currentControl as CMSModules_PortalEngine_Controls_WebParts_WebPartZoneProperties;
Line 129: if ((webPartZonePropertiesElem != null) && webPartZonePropertiesElem.Save())
Line 130: {


Solution: add the ASPX file this thingy

<%@ Register Src="~/CMSModules/PortalEngine/Controls/WebParts/WebPartZoneProperties.ascx"
    TagName="WebPartZoneProperties" TagPrefix="cms" %>