error C2017: illegal escape sequence

Compilor is showing "error C2017: illegal escape sequence" to this part of my code.(It's inside Header file and showing error everywhere this macro is being called).

 #define PROTO_TREE_ADD_HEADER( ife_tree, ife_command, element_start, element_length, proto_item_ti )                                         \
    proto_tree *sub_tree = proto_tree_add_subtree_format(ife_tree, tvb, element_start, ife_numberOfElements*(element_length),             \
    ett_cidsifecmd_tree, &proto_item_ti, " %s ( %u entries ) ", try_val_to_str( (ife_command),command_name_var ),ife_numberOfElements      \
    );

what could be the reason? thanks