His problem is that when he converted his Tekkit 1.0.0 map to the 1.1.4 version using mIDas, the pipes he and other players placed are now invisible. The pipes are still there, but he cannot use or see the pipes. Mousing over where the pipe would be gives a block box indicating the pipe's outline. Attempting to break the pipe will yield no dropped block. I had this problem too on my server. Luckily, I didn't have much pipes on the server and simply just replaced them all using NEI.