dear gromacs users when i run do_dssp program 4.5 and 4.6 i saw below error plz help me progran do_dssp, version 4.5.3 source code file:do_dsso.c, line: 521 fatal error: failed to execute command: /usr/local/bin/dssp -na dd5iLsk0 ddj8721A > /dev/null2> /dev/null best regards elham tazikeh