diff --git a/gendarme/rules/Gendarme.Rules.BadPractice/DisableDebuggingCodeRule.cs b/gendarme/rules/Gendarme.Rules.BadPractice/DisableDebuggingCodeRule.cs
index ccb7a8a24..d5393756e 100644
--- a/gendarme/rules/Gendarme.Rules.BadPractice/DisableDebuggingCodeRule.cs
+++ b/gendarme/rules/Gendarme.Rules.BadPractice/DisableDebuggingCodeRule.cs
@@ -151,7 +151,11 @@ public RuleResult CheckMethod (MethodDefinition method)
 					continue;
 
 				// ... to System.Console ...
-				MethodReference mr = (ins.Operand as MethodReference);
+				MethodReference mr = ins.Operand as MethodReference;
+                
+                if (mr == null)
+                    continue;
+
 				if (!mr.DeclaringType.IsNamed ("System", "Console"))
 					continue;
 
diff --git a/gendarme/rules/Gendarme.Rules.Interoperability/GetLastErrorMustBeCalledRightAfterPInvokeRule.cs b/gendarme/rules/Gendarme.Rules.Interoperability/GetLastErrorMustBeCalledRightAfterPInvokeRule.cs
index 63655d039..37b5dad90 100644
--- a/gendarme/rules/Gendarme.Rules.Interoperability/GetLastErrorMustBeCalledRightAfterPInvokeRule.cs
+++ b/gendarme/rules/Gendarme.Rules.Interoperability/GetLastErrorMustBeCalledRightAfterPInvokeRule.cs
@@ -135,12 +135,17 @@ private bool CheckPInvoke (Instruction startInstruction)
 
 					//check if a method is called
 					if (ins.OpCode.FlowControl == FlowControl.Call) {
+					    MethodReference mRef = ins.Operand as MethodReference;
 
-						MethodDefinition mDef = (ins.Operand as MethodReference).Resolve ();
+                        if (mRef == null) {
+                            continue;
+                        }
+
+					    MethodDefinition mDef = mRef.Resolve();
 						if (mDef != null && mDef.IsPInvokeImpl) { //check if another pinvoke method is called, this counts as "GetLastError not called"
 							break;
 						}
-
+                        
 						string s = (mDef == null) ? String.Empty : mDef.DeclaringType.GetFullName ();
 						switch (s) {
 						case "System.Runtime.InteropServices.Marshal":
diff --git a/gendarme/rules/Gendarme.Rules.Naming/AvoidDeepNamespaceHierarchyRule.cs b/gendarme/rules/Gendarme.Rules.Naming/AvoidDeepNamespaceHierarchyRule.cs
index a49442f3c..ac7756b11 100644
--- a/gendarme/rules/Gendarme.Rules.Naming/AvoidDeepNamespaceHierarchyRule.cs
+++ b/gendarme/rules/Gendarme.Rules.Naming/AvoidDeepNamespaceHierarchyRule.cs
@@ -96,7 +96,10 @@ public class AvoidDeepNamespaceHierarchyRule : Rule, IAssemblyRule {
 		[DefaultValue (DefaultMaxDepth)]
 		[Description ("The depth at which namespaces may be nested without triggering a defect.")]
 		public int MaxDepth {
-			get { return max_depth; }
+			get
+			{
+				return max_depth;
+			}
 			set {
 				if (value < 1)
 					throw new ArgumentOutOfRangeException ("MaxDepth", "Minimum: 1");
@@ -149,5 +152,14 @@ public RuleResult CheckAssembly (AssemblyDefinition assembly)
 			}
 			return Runner.CurrentRuleResult;
 		}
+
+		public override string Solution
+		{
+			get
+			{
+				return string.Format("Try to keep the depth below {0}, with an additional one for specialization (e.g. Design, Interop, Permissions).",
+					MaxDepth);
+			}
+		}
 	}
 }