Error in base64 module

[jun won, Seo]

Hi,,

I have a string "xde9usauwd8"
I want to base64decoding that string "xde9usauwd8".

examply,
In PHP3's function imap_base64()

  result = imap_base64("xde9usauwd8")

    result is "Å×½ºÆ®Áß"

but Python 1.5.2

    import base64
    result = base64.decodestring("xde9usauwd8")

I meat a Error Message

binascii.Error: Incorrect padding

Why?..
Error in Python's base64 module?