diff --git a/src/Spring/Spring.Core/Proxy/DynamicProxyManager.cs b/src/Spring/Spring.Core/Proxy/DynamicProxyManager.cs
index 478f78b2..ee092327 100644
--- a/src/Spring/Spring.Core/Proxy/DynamicProxyManager.cs
+++ b/src/Spring/Spring.Core/Proxy/DynamicProxyManager.cs
@@ -30,9 +30,9 @@ using Spring.Util;
 
 namespace Spring.Proxy
 {
-	/// <summary>
+    /// <summary>
     /// Allows easy access to existing and creation of new dynamic proxies.
-	/// </summary>
+    /// </summary>
     /// <author>Aleksandar Seovic</author>
     /// <author>Bruno Baia</author>
     public sealed class DynamicProxyManager
@@ -43,7 +43,7 @@ namespace Spring.Proxy
         /// The name of the assembly that defines proxy types created.
         /// </summary>
         public const string ASSEMBLY_NAME = "Spring.Proxy";
-        
+
         /// <summary>
         /// The attributes of the proxy type to generate.
         /// </summary>
@@ -62,14 +62,30 @@ namespace Spring.Proxy
         public static TypeBuilder CreateTypeBuilder(string typeName, Type baseType)
         {
             ModuleBuilder module = DynamicCodeManager.GetModuleBuilder(ASSEMBLY_NAME);
-            
-            if (baseType == null)
+
+            try
             {
-                return module.DefineType(typeName, TYPE_ATTRIBUTES);
+                if (baseType == null)
+                {
+                    return module.DefineType(typeName, TYPE_ATTRIBUTES);
+                }
+                else
+                {
+                    return module.DefineType(typeName, TYPE_ATTRIBUTES, baseType);
+                }
             }
-            else
+            catch (ArgumentException ex)
             {
-                return module.DefineType(typeName, TYPE_ATTRIBUTES, baseType);
+                Type alreadyRegisteredType = module.GetType(typeName, true);
+
+                string msg;
+                
+                if (alreadyRegisteredType != null)
+                    msg = "Proxy already registered for \"{0}\" as Type \"{1}\".";
+                else
+                    msg = "Proxy already registered for \"{0}\".";
+
+                throw new ArgumentException(string.Format(msg, typeName, alreadyRegisteredType.FullName), ex);
             }
         }
 
@@ -80,7 +96,7 @@ namespace Spring.Proxy
         [Conditional("DEBUG_DYNAMIC")]
         public static void SaveAssembly()
         {
-            DynamicCodeManager.SaveAssembly( ASSEMBLY_NAME );
+            DynamicCodeManager.SaveAssembly(ASSEMBLY_NAME);
         }
 
         #endregion
diff --git a/test/Spring/Spring.Core.Tests/Proxy/DynamicProxyManagerTests.cs b/test/Spring/Spring.Core.Tests/Proxy/DynamicProxyManagerTests.cs
index f8b1cea7..4bf85141 100644
--- a/test/Spring/Spring.Core.Tests/Proxy/DynamicProxyManagerTests.cs
+++ b/test/Spring/Spring.Core.Tests/Proxy/DynamicProxyManagerTests.cs
@@ -24,6 +24,7 @@ using System;
 using System.Reflection.Emit;
 using System.Threading;
 using NUnit.Framework;
+using System.Reflection;
 
 #endregion
 
@@ -82,11 +83,19 @@ namespace Spring.Proxy
         #endregion WorkerThread Class
 
         [Test]
-        [ExpectedException(typeof(ArgumentException))]
         public void CreateTypeBuilderMustNotBeCalledTwiceWithSameArguments()
         {
             TypeBuilder tb1 = DynamicProxyManager.CreateTypeBuilder("testtypename", null);
-            TypeBuilder tb2 = DynamicProxyManager.CreateTypeBuilder("testtypename", typeof(AbstractProxyTypeBuilder) );
+            
+            try
+            {
+                TypeBuilder tb2 = DynamicProxyManager.CreateTypeBuilder("testtypename", typeof(AbstractProxyTypeBuilder));
+                Assert.Fail("Did not throw expected ArgumentException.");
+            }
+            catch (ArgumentException)
+            {
+            }
+            
         }
 
         [Test]
diff --git a/test/Spring/Spring.Services.Tests/EnterpriseServices/ServicedComponentExporterTests.cs b/test/Spring/Spring.Services.Tests/EnterpriseServices/ServicedComponentExporterTests.cs
index ff8173ef..8326fb4f 100644
--- a/test/Spring/Spring.Services.Tests/EnterpriseServices/ServicedComponentExporterTests.cs
+++ b/test/Spring/Spring.Services.Tests/EnterpriseServices/ServicedComponentExporterTests.cs
@@ -54,11 +54,19 @@ namespace Spring.EnterpriseServices
         }
 
         [Test]
-        [ExpectedException(typeof(ArgumentException))]
         public void BailsWhenNotConfigured()
         {
             ServicedComponentExporter exp = new ServicedComponentExporter();
-            exp.AfterPropertiesSet();
+            try
+            {
+                exp.AfterPropertiesSet();
+                Assert.Fail("Did not throw expected ArgumentException!");
+            }
+            catch (ArgumentException)
+            {
+                
+            }
+           
         }
 
         [Test]