Weird problem....

g_nokia is always the "first" module for usb connection that is
loaded at boot. g_file_storage is loaded if user chooses file
storage when usb cable is plugged...

... which brings to first question: does file storage mode work
as expected ?

Second thing is to try first select g_ether, then plug usb cable
and when pc suite/mass storage requester appears, tap
outside of the dialog and see if it crashes again.

I just tested against linux: first chose g_ether. Then configured
usb0 interface, plugged cable and chose g_nokia (which doesn't
do anything when g_ether is chosen). No problem with connection.

Software version (see product information in settings window)
3.2010.02-8

We also test reqularly with windows ... and I just asked my
colleaque about crashing -- she tested yesterday with windows
and did not get a crash.

I wonder what kind of message from usb could crash the
device (or is it about signal levels that comes via the port)...
You could also try using another usb port and/or another
machine to lessen the change that there is some problem
with hardware ?

Also, what is your windows system and anything you can
tell how it sees the usb hardware (driver info). That information
could be useful.