Instance startup problems

Hi,

We are facing to instance startup problems that occur randomly.
Some days for a given WOApp, some instances cannot be reached by the
users.
Yet Monitor displays these instances as active (status=3D"On").
We need to use the button "Force to Quit This Instance" in the
"Configuring Instance" panel in order to restart them
else many users share a limited number of instances and the WOApp
performances decrease.

Have you ever met this kind of problem ?
Is there a solution ?

Our setup is the following :
- Windows 2000 or Windows 2003 servers,
- WebObjects 5.2.3,
- java 1.4 (j2sdk-1_4_2_10)
(Note that the pb has also been noticed in previous version of WO and
Java).

The instances are in auto-recover mode.
They run all day long
but at dawn, we shut them down through a cmd script file
which successively stops the http server iis=20
(net stop "Service de publication World Wide Web"),
cuts the wotaskd service (net stop "Apple WebObjects Task Daemon 5"),
and kills the java.exe process ( kill -f java.exe).
Then we restart the wotask and the http services.

Thank you for your answers,
Best regards