using full atom constraint in docking

Hello,

I am performing protein-protein docking with multiple constraints. I applied the constraints in full  atom mode with these two commands:

-constraints:cst_fa_file myconstraint.cst
-constraints:cst_fa_weight 10

After running docking, I get an error  saying "Can't read constraints from empty file!". While the constraint file is  not empty. It is noteworthy to mention that if I use  the same structure and the same constraint file with relax with the flag above, it would successfully run. But I am not sure why it cannot run with docking.

I am attaching docking xml, docking option and docking log.

Any suggestions would be really appreciated.