Windows 7 QEMU tap: Could not open 'TAP'

[iwl]

I have installed the openvpn TAP Driver on Windows 7 64, renamed the TAP-Network-Card to TAB but can't get it in QEMU 1.3:

qemu-system-armw.exe: -net tap,ifname=TAP: Device 'tap' could not be initialized
tap: Could not open 'TAP'

I tryed to deleta a TAB-Devices and reinstall it with the openvpn scripts allready, does not help.