[ns] error when compiling multi agent extension for ns 2.28

[Hichem AYARI]

hello
i tried to compile multi agent extension to ns 2.28. I get the mobile extention wrote by Kunal Shah but when i compile i get the following error:

common/simulator.o:simulator.cc:(.text+0x0): multiple definition of `Simulator::
command(int, char const* const*)'
common/simulator.o:simulator.cc:(.text+0x0): first defined here
common/simulator.o:simulator.cc:(.text+0x492): multiple definition of `Simulator
::alloc(int)'
common/simulator.o:simulator.cc:(.text+0x492): first defined here
common/simulator.o:simulator.cc:(.text+0xa26): multiple definition of `Simulator
::node_id_by_addr(int)'
common/simulator.o:simulator.cc:(.text+0xa26): first defined here
common/simulator.o:simulator.cc:(.text+0xac4): multiple definition of `Simulator
::append_addr(int, int*)'
.
.
.
asim/asim.o:asim.cc:(.text+0x100): first defined here
collect2: ld returned 1 exit status
make: *** [ns] Error 1

does any one have an idea about the cause of this error

Thanks
Hichem