There was a library of dynamic Linq extensions methods released as a sample with VS2008. I'd like to extend it with a Join method. The code below fails with a parameter miss match exception at run time. Can anyone find the problem?

public static IQueryable Join(this IQueryable outer, IEnumerable inner, 
  string outerSelector, string innerSelector, string resultsSelector, 
  params object[] values)
    {
        if (inner == null)
          throw new ArgumentNullException("inner");
        if (outerSelector == null)
          throw new ArgumentNullException("outerSelector");
        if (innerSelector == null)
          throw new ArgumentNullException("innerSelector");
        if (resultsSelector == null) 
          throw new ArgumentNullException("resultsSelctor");

        LambdaExpression outerSelectorLambda = 
          DynamicExpression.ParseLambda(outer.ElementType, null, 
            outerSelector, values);
        LambdaExpression innerSelectorLambda = 
          DynamicExpression.ParseLambda(inner.AsQueryable().ElementType, 
            null, innerSelector, values);

        ParameterExpression[] parameters = new ParameterExpression[] {
            Expression.Parameter(outer.ElementType, "outer"), 
            Expression.Parameter(inner.AsQueryable().ElementType, 
            "inner") };
        LambdaExpression resultsSelectorLambda = 
          DynamicExpression.ParseLambda(parameters, null, 
            resultsSelector, values);

        return outer.Provider.CreateQuery(
            Expression.Call(
                typeof(Queryable), "Join", new Type[] {
                  outer.ElementType, 
                  inner.AsQueryable().ElementType,
                  outerSelectorLambda.Body.Type, 
                  innerSelectorLambda.Body.Type, 
                  resultsSelectorLambda.Body.Type  },
                outer.Expression, inner.AsQueryable().Expression, 
                Expression.Quote(outerSelectorLambda), 
                Expression.Quote(innerSelectorLambda), 
                Expression.Quote(resultsSelectorLambda)));
    }

I've now fixed it myself, here's the answer. Please vote it up or add a better one.