--- madwifi.old/net80211/ieee80211_beacon.c	2006-11-22 12:44:03.000000000 +0100
+++ madwifi.dev/net80211/ieee80211_beacon.c	2006-11-22 12:44:34.000000000 +0100
@@ -514,7 +514,7 @@
 			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;
 		}