Issue With Mono 2.10.11

Exception!

System.InvalidOperationException: There was an error reflecting type 'MonoXmlSerializerBug1.SearchOrTeachCalloutData'.   at System.Xml.Serialization.XmlReflectionImporter.ImportTypeMapping (System.Xml.Serialization.TypeData typeData, System.Xml.Serialization.XmlRootAttribute root, System.String defaultNamespace) [0x0017a] in /Users/builder/data/lanes/mono-mac-ui-refresh-2-10/2baeee2f/source/bockbuild/profiles/mono-2-10/build-root/mono-2.10.11/_build/mono-2.10.11.git/mcs/class/System.XML/System.Xml.Serialization/XmlReflectionImporter.cs:240 
  at System.Xml.Serialization.XmlReflectionImporter.ImportTypeMapping (System.Type type, System.Xml.Serialization.XmlRootAttribute root, System.String defaultNamespace) [0x00047] in /Users/builder/data/lanes/mono-mac-ui-refresh-2-10/2baeee2f/source/bockbuild/profiles/mono-2-10/build-root/mono-2.10.11/_build/mono-2.10.11.git/mcs/class/System.XML/System.Xml.Serialization/XmlReflectionImporter.cs:195 
  at System.Xml.Serialization.XmlSerializer..ctor (System.Type type, System.Xml.Serialization.XmlAttributeOverrides overrides, System.Type[] extraTypes, System.Xml.Serialization.XmlRootAttribute root, System.String defaultNamespace) [0x0004d] in /Users/builder/data/lanes/mono-mac-ui-refresh-2-10/2baeee2f/source/bockbuild/profiles/mono-2-10/build-root/mono-2.10.11/_build/mono-2.10.11.git/mcs/class/System.XML/System.Xml.Serialization/XmlSerializer.cs:227 
  at System.Xml.Serialization.XmlSerializer..ctor (System.Type type) [0x00000] in <filename unknown>:0 
  at MonoXmlSerializerBug1.Program.SerializeToString (System.Object o) [0x0000d] in /Users/xamarin76/Projects/MonoXmlSerializerBug1/MonoXmlSerializerBug1/Program.cs:40 
  at MonoXmlSerializerBug1.Program.Main (System.String[] args) [0x00006] in /Users/xamarin76/Projects/MonoXmlSerializerBug1/MonoXmlSerializerBug1/Program.cs:16 
Inner exception: MonoXmlSerializerBug1.BaseTeachCalloutData cannot be serialized because it does not have a default public constructor   at System.Xml.Serialization.ReflectionHelper.CheckSerializableType (System.Type type, Boolean allowPrivateConstructors) [0x00046] in /Users/builder/data/lanes/mono-mac-ui-refresh-2-10/2baeee2f/source/bockbuild/profiles/mono-2-10/build-root/mono-2.10.11/_build/mono-2.10.11.git/mcs/class/System.XML/System.Xml.Serialization/ReflectionHelper.cs:87 
  at System.Xml.Serialization.XmlReflectionImporter.ImportClassMapping (System.Xml.Serialization.TypeData typeData, System.Xml.Serialization.XmlRootAttribute root, System.String defaultNamespace) [0x00030] in /Users/builder/data/lanes/mono-mac-ui-refresh-2-10/2baeee2f/source/bockbuild/profiles/mono-2-10/build-root/mono-2.10.11/_build/mono-2.10.11.git/mcs/class/System.XML/System.Xml.Serialization/XmlReflectionImporter.cs:340 
  at System.Xml.Serialization.XmlReflectionImporter.ImportClassMapping (System.Type type, System.Xml.Serialization.XmlRootAttribute root, System.String defaultNamespace) [0x00007] in /Users/builder/data/lanes/mono-mac-ui-refresh-2-10/2baeee2f/source/bockbuild/profiles/mono-2-10/build-root/mono-2.10.11/_build/mono-2.10.11.git/mcs/class/System.XML/System.Xml.Serialization/XmlReflectionImporter.cs:329 
  at System.Xml.Serialization.XmlReflectionImporter.ImportClassMapping (System.Xml.Serialization.TypeData typeData, System.Xml.Serialization.XmlRootAttribute root, System.String defaultNamespace) [0x001d8] in /Users/builder/data/lanes/mono-mac-ui-refresh-2-10/2baeee2f/source/bockbuild/profiles/mono-2-10/build-root/mono-2.10.11/_build/mono-2.10.11.git/mcs/class/System.XML/System.Xml.Serialization/XmlReflectionImporter.cs:372 
  at System.Xml.Serialization.XmlReflectionImporter.ImportTypeMapping (System.Xml.Serialization.TypeData typeData, System.Xml.Serialization.XmlRootAttribute root, System.String defaultNamespace) [0x00074] in /Users/builder/data/lanes/mono-mac-ui-refresh-2-10/2baeee2f/source/bockbuild/profiles/mono-2-10/build-root/mono-2.10.11/_build/mono-2.10.11.git/mcs/class/System.XML/System.Xml.Serialization/XmlReflectionImporter.cs:220