Error when searching

Hi guys,

When I try to use the search box to search for an item on my site I'm getting this error, does anyone know what might be the root of the problem?


[MissingMethodException: Method not found: 'NopSolutions.NopCommerce.BusinessLogic.Categories.Category NopSolutions.NopCommerce.BusinessLogic.Categories.CategoryManager.GetCategoryByName(System.String)'.]
   NopSolutions.NopCommerce.Web.Modules.SearchControl.BindData() +0
   NopSolutions.NopCommerce.Web.Modules.SearchControl.Page_Load(Object sender, EventArgs e) +155
   System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e) +14
   System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e) +35
   System.Web.UI.Control.OnLoad(EventArgs e) +91
   System.Web.UI.Control.LoadRecursive() +74
   System.Web.UI.Control.LoadRecursive() +146
   System.Web.UI.Control.LoadRecursive() +146
   System.Web.UI.Control.LoadRecursive() +146
   System.Web.UI.Control.LoadRecursive() +146
   System.Web.UI.Control.LoadRecursive() +146
   System.Web.UI.Control.LoadRecursive() +146
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +2207

I went back and uploaded all of the original DLL files and it fixed the problem. Apparently somewhere along the line I must have deleted one of those files?? I have no idea how that happened, but that was the fix.