fixed small, but annoying bugs in VB Lexer and profiler

src/AddIns/Analysis/Profiler/Controller/Data/PerformanceCounterDescriptor.cs

@@ -97,6 +97,7 @@ namespace ICSharpCode.Profiler.Controller.Data
 		/// </summary>
 		public static string GetProcessInstanceName(int pid)
 		{
+			try {
 				PerformanceCounterCategory cat = new PerformanceCounterCategory("Process");
 
 				string[] instances = cat.GetInstanceNames();
@@ -107,6 +108,9 @@ namespace ICSharpCode.Profiler.Controller.Data
 							return instance;
 					}
 				}
+			} catch (Exception) {
+				return null;
+			}
 			
 			return null;
 		}

src/Libraries/NRefactory/Project/Src/Lexer/VBNet/Lexer.cs

@@ -61,7 +61,7 @@ namespace ICSharpCode.NRefactory.Parser.VB
 					char ch = (char)nextChar;
 					#region XML mode
 					CheckXMLState(startLocation);
-					if (inXmlMode && xmlModeStack.Peek().level <= 0 && !xmlModeStack.Peek().isDocumentStart && !xmlModeStack.Peek().inXmlTag) {
+					if (inXmlMode && xmlModeStack.Count > 0 && xmlModeStack.Peek().level <= 0 && !xmlModeStack.Peek().isDocumentStart && !xmlModeStack.Peek().inXmlTag) {
 						XmlModeInfo info = xmlModeStack.Peek();
 						int peek = nextChar;
 						while (true) {
@@ -361,6 +361,7 @@ namespace ICSharpCode.NRefactory.Parser.VB
 			}
 		}
 
+		[Conditional("DEBUG")]
 		void CheckXMLState(Location startLocation)
 		{
 			if (inXmlMode && !xmlModeStack.Any())