diff --git a/lib_f90/lib_nx_read.f90 b/lib_f90/lib_nx_read.f90
index cc82b411..4fa07570 100644
--- a/lib_f90/lib_nx_read.f90
+++ b/lib_f90/lib_nx_read.f90
@@ -86,7 +86,7 @@ subroutine nx_read_scattering(infile, &
 !character(kind=C_CHAR, len=:), allocatable :: dname
 !
 !
-call forpy_start()                   ! If needed, start forpy
+call forpy_start(ier_num)                   ! If needed, start forpy
 !
 ier_num = cast(p_infile, infile(1:len_trim(infile)) )
 ier_num = tuple_create(p_args, 1)
@@ -464,7 +464,7 @@ subroutine nx_read_structure(python_script_dir, infile, unit_cell_lengths, unit_
              /
 !
 !
-call forpy_start()                   ! If needed, start forpy
+call forpy_start(ier_num)                   ! If needed, start forpy
 !
 !write(*,*) ' INFILE >',infile(1:len_trim(infile)),'<' 
 ier_num = cast(p_infile, infile(1:len_trim(infile)) )
diff --git a/lib_f90/lib_nx_write.f90 b/lib_f90/lib_nx_write.f90
index c90029a6..494da363 100644
--- a/lib_f90/lib_nx_write.f90
+++ b/lib_f90/lib_nx_write.f90
@@ -150,7 +150,7 @@ subroutine nx_write_scattering(outfile, program_version, author,
 !
 !
 ier_num = 0
-call forpy_start()
+call forpy_start(ier_num)
 !
 !
 ier_num = cast(          p_outfile,     outfile(1:len_trim(outfile)) )
@@ -386,7 +386,7 @@ subroutine nx_write_structure(python_script_dir, outfile, program_version, autho
 !types_names_string = 
 !
 ier_num = 0
-call forpy_start()
+call forpy_start(ier_num)
 !
 ier_num = cast(          p_outfile,     outfile(1:len_trim(outfile)) )
 ier_num = cast(          p_program,     program_version(1:len_trim(program_version)) )