Broadcom wlan chip is detected and modprobed correctly but does not work

I am running Kubuntu Dapper Drake. The problem is that the setup detects my Broadcom wlan chip correctly and modprobes it. The list on http://openfacts.berlios.de/index-en.phtml?title=Bcm43xxDevices says that my device is supported so everything should be fine.

When I reload the module this appears in the syslog:
Feb 1 20:51:01 localhost kernel: [4301240.546000] ACPI: PCI interrupt for device 0000:00:06.0 disabled
Feb 1 20:51:09 localhost kernel: [4301248.453000] ieee80211: 802.11 data/management/control stack, git-1.1.7
Feb 1 20:51:09 localhost kernel: [4301248.453000] ieee80211: Copyright (C) 2004-2005 Intel Corporation <email address hidden>
Feb 1 20:51:09 localhost kernel: [4301248.458000] bcm43xx driver 0.0.1
Feb 1 20:51:09 localhost kernel: [4301248.458000] ACPI: PCI Interrupt 0000:00:06.0[A] -> GSI 18 (level, low) -> IRQ 201

I think that this is fine, too.

iwconfig says this:
          eth1 IEEE 802.11b/g ESSID:off/any Nickname:"Broadcom 4318"
          Mode:Managed Access Point: Invalid Bit Rate=1 Mb/s
          Tx-Power=off
          RTS thr:off Fragment thr:off
          Encryption key:off

fine, too I think.

But when I try to scan for wlan access points this appears:
                eth1 Interface doesn't support scanning : No such device

So I installed network manager and my syslog says interesting things that may be interesting for you:

                                Feb 1 20:56:29 localhost kernel: [4301568.599000] bcm43xx: Error: Microcode "bcm43xx_microcode5.fw" not available or load failed.
Feb 1 20:56:34 localhost NetworkManager: <WARNING>^I (): nm_system_device_set_up_down_with_iface() could not bring device eth1 up. errno = 2
Feb 1 20:56:34 localhost firmware_helper[8789]: main: error loading '/lib/firmware/bcm43xx_microcode5.fw' for device '/class/firmware/0000:00:06.0' with driver 'bcm43xx driver 0.0.1'

lspci -v cutting:

0000:00:06.0 Network controller: Broadcom Corporation BCM4318 [AirForce One 54g] 802.11g Wireless LAN Controller (rev 02)
        Subsystem: Unknown device 17f9:0006
        Flags: fast devsel, IRQ 201
        Memory at d0000000 (32-bit, non-prefetchable) [size=8K]

Please tell me which further information you need to fix this.