The constructor of threading.Timer does not correctly
handle arguments passed to it, see example given. I
noted the bug in Python 2.4.1 and checked it also for
Python 2.4.2:

>>> def test(*args,**kwds): print "test: args
=",args,"and kwds =",kwds
...
>>> import threading
>>> t = threading.Timer(2,test,"hello")
>>> t.start()
>>> test: args = ('h', 'e', 'l', 'l', 'o') and kwds = {}

Proposed bug fix in threading.Timer.__init__:

    def __init__(self, interval, function, args=[],
kwargs={}): # bug
    def __init__(self, interval, function, *args,
**kwargs):    # correction

After proposed correction, rerun of test results in:

>>> t.start()
>>> test: args = ('hallo',) and kwds = {}

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user_id=38376

The implemented behaviour is the documented behaviour (it's
the same for both Thread and Timer).  You're not supposed to
"call" the Thread constructor; you're supposed to pass in
the arguments using keyword arguments.  See the library
reference for details.