Throw a consistent exception when the ProviderElement's factory canno…

…t b initialized. Fixes #151

Enyim.Caching/Configuration/ProviderElement.cs

@@ -70,8 +70,17 @@ public T CreateInstance()
 				var type = this.Factory;
 				if (type != null)
 				{
-					this.factoryInstance = (IProviderFactory<T>)FastActivator.Create(type);
-					this.factoryInstance.Initialize(this.parameters);
+					try
+					{
+						var instance = (IProviderFactory<T>)FastActivator.Create(type);
+						instance.Initialize(this.parameters);
+
+						this.factoryInstance = instance;
+					}
+					catch (Exception e)
+					{
+						throw new InvalidOperationException(String.Format("Could not initialize the provider factory {0}. Check the InnerException for details.", type), e);
+					}
 				}
 			}
 
@@ -109,20 +118,20 @@ protected override void PostDeserialize()
 
 #region [ License information          ]
 /* ************************************************************
- * 
+ *
  *    Copyright (c) 2010 Attila Kiskó, enyim.com
- *    
+ *
  *    Licensed under the Apache License, Version 2.0 (the "License");
  *    you may not use this file except in compliance with the License.
  *    You may obtain a copy of the License at
- *    
+ *
  *        http://www.apache.org/licenses/LICENSE-2.0
- *    
+ *
  *    Unless required by applicable law or agreed to in writing, software
  *    distributed under the License is distributed on an "AS IS" BASIS,
  *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  *    See the License for the specific language governing permissions and
  *    limitations under the License.
- *    
+ *
  * ************************************************************/
 #endregion