ReGen Chunk in selfmade World

[xoft]

That should work. For some reason it seems that the blockarea is not read from the source world (you should check for failures - it returns a boolean).
For troubleshooting, what does ba:GetDataValues() return after the Read() call?
Or it could be some weird API binding failure, Write() function mis-interpreting one of its parameters. Try using ba:Write(DestWorld, startX, 2, startZ, cBlockArea.baTypes + cBlockArea.baMetas)

Also, I forgot that there needs to be one more ChunkStay, for the DestWorld, inside the DestWorld:QueueTask()'s callback:

   ...
   DestWorld:QueueTask(
     function()
       DestWorld:ChunkStay({{chunkx, chunkz}}, nil,
         function()
           ba:Write(DestWorld, startX, 2, startZ)
           ba:Clear()
         end  -- ChunkStay callback
       )
     end  -- QueueTask callback
   )
   ...