"'UnityEngine.GUI.DoTextField' is inaccessible due to its protection level."

I found a very cool snippet of code by Shaun on this page: http://forum.unity3d.com/threads/14505-non-selectable-textarea

And tweaked it a bit to come up with this:

    var searchFieldID : int = GUIUtility.GetControlID(FocusType.Keyboard);
    var searchFieldRect : Rect = GUILayoutUtility.GetRect((worldListFilter == "" ? 400 : 255), 28, "textfield");
    var worldListFilterGUI : GUIContent = GUIContent(worldListFilter);
    GUI.DoTextField(searchFieldRect, searchFieldID, worldListFilterGUI, false, (worldListFilter == "" ? 400 : 255), "TextField");
    worldListFilter = worldListFilterGUI.text;
    if (!searchFieldRect.Contains(Event.current.mousePosition) && GUIUtility.keyboardControl != searchFieldID && String.IsNullOrEmpty(worldListFilter))
        GUI.Label(searchFieldRect, "Title, Author, or Description","textfieldhint");

It's supposed to display a search field UI style alt text when the user isn't ineracting with the field, but alas - won't compile and instead Unity throws an "'UnityEngine.GUI.DoTextField' is inaccessible due to its protection level" error.

Any ideas?

There is no GUI.DoTextField function. Or rather, there is, but it's private (as the error basically says). Private APIs can no longer be accessed in Unity 3, so they might as well not exist...they were never intended to be used by user code in the first place, and are subject to change at any time.