Why optparse wont import?

[Karlo Lozovina]

If I create a file with only one line:

---
from optparse import OptionParser
---

I get this when I try to run it from "DOS" prompt:

Traceback (most recent call last):
  File "optparse.py", line 1, in ?
    from optparse import OptionParser
  File "X:\data\other\source\python\population\optparse.py", line 1, in ?
    from optparse import OptionParser
ImportError: cannot import name OptionParser

When I try to do that from Python prompt everything works fine. What's the 
problem?

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