fix unhandled exception when attaching.

src/AddIns/Debugger/Debugger.AddIn/Service/WindowsDebugger.cs

@@ -887,6 +887,13 @@ namespace ICSharpCode.SharpDevelop.Services
 		
 		void process_Modules_Added(object sender, CollectionItemEventArgs<Module> e)
         {
+			if (ProjectService.OpenSolution == null ||
+			    ProjectService.OpenSolution.Projects == null ||
+			    ProjectService.OpenSolution.Projects.Count() == 0)
+				return;
+			
+			if (e == null || e.Item == null) return;
+			
             ProjectService.OpenSolution.Projects
                 .Where(p => e.Item.Name.IndexOf(p.Name) >= 0)
             	.ForEach(p => e.Item.LoadSymbolsFromDisk(new []{ Path.GetDirectoryName(p.OutputAssemblyFullPath) }));