I screwed up bad I dont know how to fix

I switched the word main and camera around I think.. and now i switched it back its giving me a bogus error. please tell me how to fix if I don't know IM SCREWED because theres no way to undo it because I saved and exited by accident..

using System.Threading;

[AddComponentMenu("VoxelEngine/WorldGenerator")] public class WorldGenerator : MonoBehaviour {

 private Map map;
 private ColumnMap columnMap = new ColumnMap();
 private TerrainGenerator terrainGenerator;
 private TreeGenerator[] treeGenerator;
 private bool building = false;
 
 
 void Awake() {
     map = GetComponent<Map>();
     terrainGenerator = new TerrainGenerator(map);
     
     Block[] woodBlocks = map.GetBlockSet().GetBlocks("Wood");
     Block[] leavesBlocks = map.GetBlockSet().GetBlocks("Leaves");
     
     treeGenerator = new TreeGenerator[ Math.Max(woodBlocks.Length, leavesBlocks.Length) ];
     for(int i=0; i<treeGenerator.Length; i++) {
         Block wood = woodBlocks[ i%woodBlocks.Length ];
         Block leaves = leavesBlocks[ i%leavesBlocks.Length ];
         treeGenerator[i] = new TreeGenerator(map, wood, leaves);
     }
 }
 
 void Update() {
     if(!building) StartCoroutine( Building() );
 }
 
 private IEnumerator Building() {
     building = true;
     Vector3 pos = Camera.CameraMain.transform.position;
     Vector3i current = Chunk.ToChunkPosition( (int)pos.x, (int)pos.y, (int)pos.z );
     Vector3i? column = columnMap.GetClosestEmptyColumn(current.x, current.z, 7);
     
     if(column.HasValue) {
         int cx = column.Value.x;
         int cz = column.Value.z;
         columnMap.SetBuilt(cx, cz);
         
         yield return StartCoroutine( GenerateColumn(cx, cz) );
         yield return null;
         ChunkSunLightComputer.ComputeRays(map, cx, cz);
         ChunkSunLightComputer.Scatter(map, columnMap, cx, cz);
         terrainGenerator.GeneratePlants(cx, cz);
         
         yield return StartCoroutine( BuildColumn(cx, cz) );
     }
     building = false;
 }
 
 private IEnumerator GenerateColumn(int cx, int cz) {
     yield return StartCoroutine( terrainGenerator.Generate(cx, cz) );
     yield return null;
     
     if(treeGenerator.Length > 0) {
         int x = cx * Chunk.SIZE_X + Chunk.SIZE_X/2;
         int z = cz * Chunk.SIZE_Z + Chunk.SIZE_Z/2;
         int y = map.GetMaxY(x, z)+1;
         int index = UnityEngine.Random.Range( 0, treeGenerator.Length );
         treeGenerator[index].Generate(x, y, z);
     }
 }
 
 public IEnumerator BuildColumn(int cx, int cz) {
     List3D<Chunk> chunks = map.GetChunks();
     for(int cy=chunks.GetMinY(); cy<chunks.GetMaxY(); cy++) {
         Chunk chunk = map.GetChunk( new Vector3i(cx, cy, cz) );
         if(chunk != null) chunk.GetChunkRendererInstance().SetDirty();
         if(chunk != null) yield return null;
     }
 }
 
 

}