Index: EventLogAppender.cs
===================================================================
--- EventLogAppender.cs	(revision 607768)
+++ EventLogAppender.cs	(working copy)
@@ -343,7 +343,17 @@
 				}
 				else
 				{
-					string eventIDPropertyString = eventIDPropertyObj as string;
+                    string eventIDPropertyString;
+                    if (eventIDPropertyObj is string)
+                    {
+                        eventIDPropertyString = (string)eventIDPropertyObj;
+                    }
+                    else
+                    {
+                        eventIDPropertyString = eventIDPropertyObj.ToString();
+
+                    }
+
 					if (eventIDPropertyString != null && eventIDPropertyString.Length > 0)
 					{
 						// Read the string property into a number