Entity use in string element

[aTCSharp]

<?xml version="1.0" encoding="utf-8"?><ArrayOfString xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">  <string>C:Program Files (x86)AVEVAPlantE3D1.1.0ExplorerAddin</string>  <string>C:Program Files (x86)AVEVAPlantE3D1.1.0DrawListAddin</string>  <string>C:Program Files (x86)AVEVAPlantE3D1.1.0MyDataAddin</string>  <string>C:Program Files (x86)AVEVAPlantE3D1.1.0HistoryAddin</string>  <string>C:Program Files (x86)AVEVAPlantE3D1.1.0ReferenceListAddin</string>  <string>C:Program Files (x86)AVEVAPlantE3D1.1.0PipeCheckAddin</string>  <string>C:Program Files (x86)AVEVAPlantE3D1.1.0FindAddin</string>  <string>C:Program Files (x86)AVEVAPlantE3D1.1.0LinksAddin</string>  <string>C:Program Files (x86)AVEVAPlantE3D1.1.0AttributesUtility</string>  <string>C:Program Files (x86)AVEVAPlantE3D1.1.0StatusControllerAddin</string>  <string>C:Program Files (x86)AVEVAPlantE3D1.1.0ModelChangesAddin</string>  <string>C:Program Files (x86)AVEVAPlantE3D1.1.0SVGCompare</string>  <string>C:Program Files (x86)AVEVAPlantE3D1.1.0InstrumentationImportAddin</string>  <string>C:Program Files (x86)AVEVAPlantE3D1.1.0AvevaNetExportConfigAddin</string>  <string>C:Program Files (x86)AVEVAPlantE3D1.1.0ReportingAddin</string>  <string>C:Program Files (x86)AVEVAPlantE3D1.1.0MessageAddin</string>  <string>C:Program Files (x86)AVEVAPlantE3D1.1.0IntegratorAddin</string>  <string>C:AtkNETaddinsdllAtkModelAddins</string></ArrayOfString>

So obviously there is a common file location which lends itself to the use of an entity (I think an entity is what I am after).

However when I defined an entity location as

<!ENTITY location "C:Program Files (x86)AVEVAPlantE3D1.1.0">

and used it in the string element declarations

e.g. <string>&location;MessageAddin</string>

I received a fatal error from the application.