card deliberately changes AP

[che]

Until recently I've been happily running on mid-2003 cvs hostap with a ZCom
XI-626 in managed mode. A few days ago, the card started to associate to an
AP with different ESSID than the one that has been set. At first it was
sufficient, though annoying, to simply set the original ESSID back.

Today the annoyance grew even stronger, because iwconfig resist every
attempt to set the ESSID with
the followith error message:
Error for wireless request "Set ESSID" (8B1A) :
    SET failed on device wlan0 ; Invalid argument.

The problem survives card resets, unloading the module and rebooting the
box. Updating to hostap 0.1.3 didn't solve the situation either. Does
anonyone have a clue what can cause such behaviour and how to get rid of it?

PS: The system runs on 2.4.21pre6 kernel.

Thanks,
	Petr Novak