bcm43xx issues an error message every minute

["Georg Heinrich" <georg.heinrich@gh-blue.de>]

Hello,

I get the following error messages about every minute on the console:

    bcm43xx: PHY connected
    bcm43xx: Microcode "bcm43xx_microcode5.fw" not available or load failed
    bcm43xx: core_up for active 802.11 core failed (-2)

The HW is:
    Apple PowerBook G4 12" (PowerBook 6,8) 1,5 GHz
    Airport Extreme, Firmware version 405.1 (3.90.34.0.p18)

What do I have to do to solve the error?
What can I do to stop those error messages showing up every minute until
the error is solved?

Any hint is welcome.
Thanks in advance,

    G. Heinrich