Index was out of range, ToLower() method does not have any arguments

This kinds of expressions

.Where( => (.Descrizione2.ToLower().Contains("aaa") = True))
.Where( => (.Descrizione2.ToLower().StartsWith("aaa") = True))
...

thrown this exception:

at System.ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument argument, ExceptionResource resource)
at System.ThrowHelper.ThrowArgumentOutOfRangeException()
at System.SZArrayHelper.get_Item[T](Int32 index)
at System.Collections.ObjectModel.ReadOnlyCollection`1.get_Item(Int32 index)
at NHibernate.Linq.Visitors.MemberNameVisitor.VisitMethodCall(MethodCallExpression expr)
at NHibernate.Linq.Visitors.ExpressionVisitor.Visit(Expression exp)
at NHibernate.Linq.Visitors.NHibernateExpressionVisitor.Visit(Expression exp)
at NHibernate.Linq.Visitors.MemberNameVisitor.GetMemberName(ICriteria rootCriteria, Expression expr)
at NHibernate.Linq.Visitors.WhereArgumentsVisitor.GetLikeCriteria(MethodCallExpression expr, MatchMode matchMode)
at NHibernate.Linq.Visitors.WhereArgumentsVisitor.VisitMethodCall(MethodCallExpression expr)
at NHibernate.Linq.Visitors.ExpressionVisitor.Visit(Expression exp)
at NHibernate.Linq.Visitors.NHibernateExpressionVisitor.Visit(Expression exp)
at NHibernate.Linq.Visitors.ExpressionVisitor.VisitLambda(LambdaExpression lambda)
at NHibernate.Linq.Visitors.ExpressionVisitor.Visit(Expression exp)
at NHibernate.Linq.Visitors.NHibernateExpressionVisitor.Visit(Expression exp)
at NHibernate.Linq.Visitors.WhereArgumentsVisitor.VisitUnary(UnaryExpression expr)
at NHibernate.Linq.Visitors.ExpressionVisitor.Visit(Expression exp)
at NHibernate.Linq.Visitors.NHibernateExpressionVisitor.Visit(Expression exp)
at NHibernate.Linq.Visitors.WhereArgumentsVisitor.GetCriterion(ICriteria rootCriteria, ISession session, Expression expression)
at NHibernate.Linq.Visitors.RootVisitor.HandleWhereCall(MethodCallExpression call)
at NHibernate.Linq.Visitors.RootVisitor.VisitMethodCall(MethodCallExpression expr)
at NHibernate.Linq.Visitors.ExpressionVisitor.Visit(Expression exp)
at NHibernate.Linq.Visitors.NHibernateExpressionVisitor.Visit(Expression exp)
at NHibernate.Linq.Visitors.RootVisitor.VisitMethodCall(MethodCallExpression expr)
at NHibernate.Linq.Visitors.ExpressionVisitor.Visit(Expression exp)
at NHibernate.Linq.Visitors.NHibernateExpressionVisitor.Visit(Expression exp)
at NHibernate.Linq.Visitors.NHibernateQueryTranslator.Translate(Expression expression, QueryOptions queryOptions)
at NHibernate.Linq.NHibernateQueryProvider.TranslateExpression(Expression expression)
at NHibernate.Linq.NHibernateQueryProvider.Execute(Expression expression)
at NHibernate.Linq.QueryProvider.System.Linq.IQueryProvider.Execute[T](Expression expression)
at System.Linq.Queryable.Count[TSource](IQueryable`1 source)

Right now with RIA based controls (custom ones but also MS standard) compose those kind of expression to solve the problem of case insentive. The problem is well described here http://www.telerik.com/community/forums/aspnet-mvc/grid/grid-and-nhibernate-linq.aspx.