Well in the case of MrPeach and nsend I am actually missing the files. In the MrPeach directory I have got no tcpsocketserver.dll file (I have and can create other objects such as tcpserver, routeOSC, etc).
The same thing happens for me with the objects you mentioned from "MrPeach" and "nsend".
Also, all the "msd" objects and all the "hardware" objects except [lanbox] are missing.
And like you say, they are missing from their respective directories. I'm running Pd-extended 0.41.4