error in emulator: ./emulator-freechips.rocketchip.system-DefaultConfig helloworld

Hi,
I am new to rocketchip and am trying to run a helloworld using emulator.
I am getting the error and the system is halted.
Error:
"tohost and fromhost symbols not in ELF; can't communicate with target"

I run this command:
./emulator-freechips.rocketchip.system-DefaultConfig helloworld
.........
Debug Abstract Command Error #3 (EXCEPTION)ERROR: ../fesvr/dtm.cc:347, Should die, but allowing simulation to continue and fail.ERROR: ../fesvr/dtm.cc:346, Debug Abstract Command Error #3 (EXCEPTION)ERRORwarning: tohost and fromhost symbols not in ELF; can't communicate with target

Please suggest me how to solve it. Any suggestion will be appreciated very much!

Start with the documented command ./emulator-freechips.rocketchip.system-DefaultConfig helloworld and inspect the helloworld ELF in relation to the reported fesvr error. Compare the emulator's expected tohost and fromhost symbols with those present in the ELF; done means helloworld runs without the communication and halt errors.

Written by the indexing model from the issue text.