Is this is bug or something change in Python 2.3

[Jeff Epler]

The reason is the difference in the way sys.path is set:

$ cat x.py
import sys; print repr(sys.path[0])
$ python2.2 ./x.py
'.'
$ python2.3 ./x.py
'/net/filesrv1/sd3a/users/jepler'

Jeff