--- E:\src\extern\nant\src\NAnt.VSNet\aa\Solution.cs	Sun Dec 28 16:47:12 2003
+++ E:\src\extern\nant\src\NAnt.VSNet\Solution.cs	Fri Jan 16 15:01:48 2004
@@ -354,6 +354,11 @@
         private void LoadProjectGuids(ArrayList projects, bool isReferenceProject) {
             foreach (string projectFileName in projects) {
                 string projectGuid = ProjectFactory.LoadGuid(projectFileName, _tfc);
+				if(_htProjectFiles[projectGuid] != null)
+					throw new BuildException(string.Format(CultureInfo.InvariantCulture,
+						"Error loading project {0}. " 
+						+ " Project GUID {1} already exists! Conflicting project is {2}."
+						, projectFileName,projectGuid,_htProjectFiles[projectGuid]));
                 _htProjectFiles[projectGuid] = projectFileName;
                 if (isReferenceProject) {
                     _htReferenceProjects[projectGuid] = null;