AttributeError: expected a callback function (and optionally one or two strings) as argument(s)

Question

I'm new to Python and was trying to do some import and export scripting in Blender 2.43(which uses Python 2.4). I had a simple script:

import Blender
import flt_import 
import export_obj
import os


select_file=flt_import.select_file(r'C:\Code\Code\Testing4Flt\sg_navysoldier.flt')
Blender.Window.FileSelector(select_file, "Import OpenFlight", "*.flt")
out_file=export_obj.write_ui(r'C:\Code\Code\Testing4Flt\sg_navysoldier.obj')
Blender.Window.FileSelector(out_file,'Export Wavefront OBJ', sys.makename(ext='.obj'))

When run, I got the error in the title at line 8. I don't really understand what it means and I tried searching it but couldn't find that error exactly. Will appreciate any help.

Edit:

Here's the full traceback.

Traceback (most recent call last):


File "Testing4.py", line 8, in ?
AttributeError:
expected a callback function (and optionally one or two strings) as argument(s)