'field' but is used like a 'type' [duplicate]

Answer 1

The definition of Class1 is incomplete. You cannot call this method within the class, you can call it within a method of the class:

using System;
using PaymentPlanLogic;
namespace PaymentPlanStoreLogic
{
    public class Class1
    {
        #region Members

        Logger myLog;

        #endregion

        #region Constructors

        public Class1()
        {
            myLog = new Logger();
            myLog.createLog();
        }

        #endregion
    }
}

Then createLog() would execute upon instantiating a new instance of Class1.