Hibernate version: 1.2 .0.4000

Mapping documents:
in OperationInfo.hpm.xml I have composed the ProgramInfo Class as:
<many-to-one name="ProgramInfo" class="ProgramInfo" column="ProgramID" access="field.camelcase-underscore" fetch="select" />


my C# code is:
{
ArrayList list = new ArrayList();
ArrayList orders = new ArrayList();
ICriterion programTypeCriteria = Expression.Eq
("ProgramInfo.ProgramType", programType);
list.Add(programTypeCriteria);

IList<OperationInfo> matchingList =
Repository<OperationInfo>.FindAll
(
(Order[])orders.ToArray(typeof(Order)),
(ICriterion[])list.ToArray(typeof(ICriterion))
);
}

when i call this code, I got this error
"could not resolve property: ProgramInfo.ProgramType of: MyNameSpace.Domain.CateringOperationInfo"


I am using SQL Server 2005.

Please if any one has usefull help !!!