221a:0100 is the ztex device, so cgminer/libusb is not detecting it.
What log output does cgminer give?
should get something like this:
[2012-07-02 23:39:57] Not a ZTEX device 8564:1000
[2012-07-02 23:39:57] Not a ZTEX device 0409:005a
[2012-07-02 23:39:57] Not a ZTEX device 0409:005a
[2012-07-02 23:39:57] Not a ZTEX device 0000:0000
[2012-07-02 23:39:57] Not a ZTEX device 0000:0000
but if you get
[2012-07-02 23:39:57] Not a ZTEX device 221a:0100
then something weird is going on.
maybe it's a bit late for me but i have only do this:
tail -f /opt/var/log/YYYYMMDD-HHMMSS..log
replacing YYYYMMDD-HHMMSS and whats with the PID?