mmm, that's strange.
Try to remove then reinsert the ath5k module, with these commands:
sudo modprobe -r ath5k
sudo modprobe ath5k
and check again if the 'wlan0' is created.
No, that changes nothing.
If it's not, check in your dmesg if there is any error explaining what's wrong.
Perhaps it's this:
[ 1623.976562] ath5k 0000:02:00.0: enabling device (0000 -> 0002)
[ 1623.976578] ath5k 0000:02:00.0: PCI INT A -> GSI 16 (level, low) -> IRQ 16
[ 1623.976599] ath5k 0000:02:00.0: setting latency timer to 64
[ 1623.976720] ath5k 0000:02:00.0: registered as 'phy0'
[ 1623.986789] ath5k phy0: failed to wakeup the MAC Chip
[ 1623.986853] ath5k 0000:02:00.0: PCI INT A disabled
[ 1623.986881] ath5k: probe of 0000:02:00.0 failed with error -5
You find the whole output of dmesg in this file: http://www.bm-kuehn.de/temp/errors.txt
(can't attach files here in the board).
Also, paste here the output of the command:
lspci | grep Ethernet
mk@mk-netbook:~$ lspci |grep Ethernet
02:00.0 Ethernet controller: Atheros Communications Inc. AR242x 802.11abg Wireless PCI Express Adapter (rev 01)
03:00.0 Ethernet controller: Marvell Technology Group Ltd. 88E8040 PCI-E Fast Ethernet Controller (rev 13)
Thanks for more help...!