How to set-up RADIUS server in hostapd

[Jagadish]

Hi,

      I am using hostapd-0.5.9. I want to use hostapd as RADIUS server. 
For this I enabled CONFIG_EAP, CONFIG_EAP_TLS and CONFIG_RADIUS_SERVER 
in .config file. It compiled successfully. But if I run it using 
"hostapd hostapd.conf", it is giving segmentation fault.
In hostapd.conf file, I added interface=wlan0. The coredump is showing 
the following function as responsible for segmentation fault.
===================================================
driver_lookup (name=0x8076f62 "default") at hostapd.c:1561
1561                     return p->ops;
====================================================
Please help me solving this problem.

thanks,
Jagadish