serialization and enum ProgramType

[Reader]

Why would this fail? When i rename the ProgramType to say.. ProramType it
works.. but if it is ProgramType the following error occurs.

An unhandled exception of type 'System.Invalid OperationExcept ion' occurred
in system.xml.dll

Additional information: There was an error reflecting

public class Program
{

/// <remarks/>
[System.Xml.Seri alization.XmlAt tributeAttribut e()]
public ProgramType Type;

/// <remarks/>
[System.Xml.Seri alization.XmlTe xtAttribute()]
public string Value;
}

public enum ProgramType
{

FooBar
}