PowerBook 280c: Hangs at Shutdown or Eject

When I try to shut down my Powerbook 280c Duo it closes all open applications and then the pointer freezes. I have to use the reset button to power down the computer. Why?
You are using an older version of the Express Modem software. To correct this problem, use Express Modem software version v1.6 or later.

These articles can help you locate the software update mentioned here:
Published Date: Feb 19, 2012