[Trac] Log issues

[Emmanuel-G BLOT]

Hi,

I often get the following error trace w/ Trac:

Traceback (most recent call last):
   File "C:\Programs\ActiveState\Python\Lib\logging\__init__.py", line 674, in emit
     msg = self.format(record)
   File "C:\Programs\ActiveState\Python\Lib\logging\__init__.py", line 567, in format
     return fmt.format(record)
   File "C:\Programs\ActiveState\Python\Lib\logging\__init__.py", line 362, in format
     record.message = record.getMessage()
   File "C:\Programs\ActiveState\Python\Lib\logging\__init__.py", line 233, in getMessage
     msg = msg % self.args
TypeError: not all arguments converted during string formatting

Whenever there is an error, Trac produces this kind of backtrace, instead of the actual error 
(trunk:1756)

It occurs both w/ Apache (2.0.54) and tracd (python 2.3)

Any idea of what could cause this problem ?
Has anyone already experienced it ?

BR,
Manu