Hi, 
I've reproduced that bug on both the win client and the
cygwin build (windows 2000).

When i do a call on writer like this :
cvsWriter = csv.writer(pseudoFichier, 'excel',
delimiter=delimiteur)

with delimiteur being a variable == ';' ,
       pseudoFichier : a cStringIO

I get that error message :

    cvsWriter = csv.writer(pseudoFichier, 'excel',
delimiter=delimiteur)
TypeError: bad argument type for built-in operation

A way to fix it is to replace the variable delimiteur
with it's value, so 

cvsWriter = csv.writer(pseudoFichier, 'excel',
delimiter=';')

works like a bliss !

I've tried to look at the source of csv.py just to see
that the method that i wanted to see is imported from a
c library (_csv.lib).
I'm not strong enough to look further.
I hope someone here will be able to find the reason of
what seems to be a bug.

Greetings,
Xavier

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user_id=44345

I can't reproduce the problem:

>>> import csv
>>> import cStringIO
>>> pseudoFichier = cStringIO.StringIO()
>>> delimiteur = ';'
>>> writer = csv.writer(pseudoFichier, 'excel', 
delimiter=delimiteur)
>>> writer.writerow([1,2,3,4])
>>> pseudoFichier.getvalue()
'1;2;3;4\r\n'