MN500 - Wireless connection is lost intermittently

My laptop has intermittently been loosing the association
with my Microsoft Wireless router. My laptop doesn't even
see the signal from my wireless router, though it can catch
and associate with neighbors' wirless routers. Usually, if
the connection is associated, then the connection stays up.

The problem of "not associating" occurs when I put the
laptop on standby in the night and wake it up in the
morning. Sometimes, when I come back from office, the
laptop wouldn't see/associate with the wireless router.

Power cycling the wirless router always fixes this problem.
Doing anything (changing the settings, restarting, flapping
the wirless card etc) at the laptop side doesn't help.

I have a WinXP with SP2 running on my IBM T42 laptop, which
has an built-in Cisco PCI (350 series) wireless adaptor.

The Wireless router is MN-500, which is running with the
following version:::
~~~~~~~~~~~~~~~~~~~~~~~
Runtime code version: V1.00.072
Boot code version: V1.02
Firmware Version: V1.00.072
Date: 07-30-2002
~~~~~~~~~~~~~~~~

Is this problem known ?
Is there any recent firmware than V1.02 ?
Please help.

Cheers,
Rajiv