T4Toolbox und MSBuildBinPath und Engine.BinPath

Hallo,
mit t4 generieren wir aus xmls diverse klassen.
sobald ich template.Output.BuildAction = "none" setze, erhalte ich folgende exception auf meinem windows 7 32bit mit VS2008, .net 3.5sp1.
hat jemand einen tip? wäre super!!!!

Error 1 An Exception was thrown while running the transformation code. The process cannot continue. The following Exception was thrown:
System.InvalidOperationException: Before a project can be instantiated, Engine.BinPath must be set to the location on disk where MSBuild is installed. This is used to evaluate $(MSBuildBinPath).
at Microsoft.Build.Shared.ErrorUtilities.ThrowInvalidOperation(String resourceName, Object[] args)
at Microsoft.Build.BuildEngine.Project..ctor(Engine engine)
at Microsoft.Build.BuildEngine.Project..ctor()
at T4Toolbox.DteProcessor.SetProjectItemProperties(ProjectItem projectItem, OutputFile output)
at T4Toolbox.DteProcessor.UpdateOutputFiles(IEnumerable1 outputFiles, Solution solution, IEnumerable1 projects, ProjectItem template)
at T4Toolbox.DteProcessor.UpdateFiles(ICollection1 outputFiles) at T4Toolbox.OutputManager.UpdateFiles() at System.AppDomain.DoCallBack(CrossAppDomainDelegate callBackDelegate) at System.AppDomain.DoCallBack(CrossAppDomainDelegate callBackDelegate) at T4Toolbox.TransformationContext.OnTransformationEnded(TextTransformation transformation) at Microsoft.VisualStudio.TextTemplating62D3FD73E5B195AC5C145E1C3A890FDA.GeneratedTextTransformation.Dispose(Boolean disposing) in c:\work\vs2008\vdmk_neu\aviitaCAF\source\aviita.CAF.common\CAFBusinessObjectsGenerator.tt:line 18 at Microsoft.VisualStudio.TextTemplating.TextTransformation.Dispose() at Microsoft.VisualStudio.TextTemplating.TransformationRunner.RunTransformation(String fullClassName, String baseClassName, String[] importedNamespaces, String[] references, String source, String inputFile, Boolean debug, SupportedLanguages language, IDictionary2 languageOptions, IFormatProvider format, ITextTemplatingEngineHost host, Boolean cacheAssemblies, String& result) 1 1