diff --git a/Makefile.Defines b/Makefile.Defines
index 1346f4b09..07126f842 100644
--- a/Makefile.Defines
+++ b/Makefile.Defines
@@ -65,13 +65,13 @@ GPAR = -fopenmp -ftree-parallelize-loops=4
 GMEM = -fsanitize=undefined -fsanitize=address -fsanitize=leak 
 GWARNINGS = -Wall -Warray-bounds  -Wimplicit-interface -Wextra -Warray-temporaries
 
-#FFLAGS  = $(IDEBUG) $(HEAPARR)
+FFLAGS  = $(IDEBUG) $(HEAPARR)
 #FFLAGS  = -init=snan,arrays -no-wrap-margin -O3 $(STRICTREAL) $(SIMDVEC) $(PAR) 
-#FORTRAN = ifort
+FORTRAN = ifort
 #AR     = xiar
 
-FORTRAN = gfortran
-FFLAGS =  -ffree-line-length-none $(GDEBUG) #$(GMEM)
+#FORTRAN = gfortran
+#FFLAGS =  -ffree-line-length-none $(GDEBUG) #$(GMEM)
 AR     = ar
 
 # DO NOT include in CFLAGS the "-c" option to compile object only
diff --git a/src/symba/symba_io.f90 b/src/symba/symba_io.f90
index 70123d5bd..6657582e0 100644
--- a/src/symba/symba_io.f90
+++ b/src/symba/symba_io.f90
@@ -272,7 +272,7 @@ module subroutine symba_io_read_frame_pl(self, iu, param, form, ierr)
       return
    end subroutine symba_io_read_frame_pl
 
-   subroutine symba_io_read_frame_info(self, iu, param, form, ierr)
+   module subroutine symba_io_read_frame_info(self, iu, param, form, ierr)
       !! author: David A. Minton
       !!
       !! Reads a single frame of a particle info data from a file.
@@ -282,6 +282,8 @@ subroutine symba_io_read_frame_info(self, iu, param, form, ierr)
       class(swiftest_parameters), intent(inout) :: param !! Current run configuration parameters 
       character(*),               intent(in)    :: form  !! Input format code ("XV" or "EL")
       integer(I4B),               intent(out)   :: ierr  !! Error code
+
+      ierr = 0
    end subroutine symba_io_read_frame_info
 
    module subroutine symba_io_read_cb_in(self, param) 
@@ -410,7 +412,7 @@ module subroutine symba_io_read_pl_in(self, param)
       return
    end subroutine symba_io_read_pl_in
 
-   subroutine symba_io_write_frame_cb(self, iu, param)
+   module subroutine symba_io_write_frame_cb(self, iu, param)
       !! author: David A. Minton
       !!
       !! Writes a single frame of a SyMBA pl file 
@@ -437,7 +439,7 @@ subroutine symba_io_write_frame_cb(self, iu, param)
       end select
    end subroutine symba_io_write_frame_cb
 
-   subroutine symba_io_write_frame_pl(self, iu, param)
+   module subroutine symba_io_write_frame_pl(self, iu, param)
       !! author: David A. Minton
       !!
       !! Writes a single frame of a SyMBA pl file