Index: madwifi-ng-r2568-20070710/net80211/ieee80211_beacon.c
===================================================================
--- madwifi-ng-r2568-20070710.orig/net80211/ieee80211_beacon.c	2007-10-20 20:52:09.000000000 +0200
+++ madwifi-ng-r2568-20070710/net80211/ieee80211_beacon.c	2007-10-20 20:52:09.000000000 +0200
@@ -518,7 +518,7 @@
 			vap->iv_flags &= ~IEEE80211_F_XRUPDATE;
 		}
 #endif
-		if (ic->ic_flags_ext & IEEE80211_FEXT_ERPUPDATE) {
+		if ((ic->ic_flags_ext & IEEE80211_FEXT_ERPUPDATE) && (bo->bo_erp != NULL)) {
 			(void) ieee80211_add_erp(bo->bo_erp, ic);
 			ic->ic_flags_ext &= ~IEEE80211_FEXT_ERPUPDATE;
 		}