c# Error: Type 'x' already defines a member called 'y' with the same parameter types
===

On VB express C#, I get the following error with the code below: 
*'Type 'myComponent.SettingsComponent' already defines a member called 'SolveInstance' with the same parameter types'* but I only used SolveInstance there. What am I doing wrong and how would I be able to solve this on my own next time?
   
      namespace myComponent
      {
      public class SettingsComponent : GH_Component
        {
        protected override void SolveInstance(IGH_DataAccess DA)
                   {
                     if (m_settings == null)
                     {
                       AddRuntimeMessage(warning, "You must declare some valid settings");
                       return;
                     }
                     DA.SetData(0, m_settings);
                   }
          }
         }