Using IList<T> with NHibernate using Server 2008 64Bit

Question

Hi, I have a class that one of its members defined like this :

[DataMember]
public virtual IList<T> RelatedXs
{
    get
    {
        return this.m_relatedXs;    
    }
    private set
    {
        this.m_related = value;
    }
}

But when I try to Save it using NHb Session object, I get this exception : "Cannot serialize member RelatedXs of type System.Collections.Generic.IList`1 [DLL INFO] because it is an interface."

The weird part is that exact code works on Windows 2003 Server 32bit, but now on Windows 2008 Server 64 bit throws this exception.

The project is defined as x86.

Any Suggestions ?