--- chan_zap.c.80501.orig	2007-09-14 14:23:48.000000000 +0200
+++ chan_zap.c.80501	2007-09-14 14:24:47.000000000 +0200
@@ -9127,7 +9127,7 @@
 									pri->pvts[chanpos]->logicalspan, pri->pvts[chanpos]->prioffset, pri->span, (int)e->hangup.aoc_units, (e->hangup.aoc_units == 1) ? "" : "s");
 
 #ifdef SUPPORT_USERUSER
-						if (!ast_strlen_zero(e->hangup.useruserinfo)) {
+						if (pri->pvts[chanpos]->owner && !ast_strlen_zero(e->hangup.useruserinfo)) {
 							pbx_builtin_setvar_helper(pri->pvts[chanpos]->owner, "USERUSERINFO", e->hangup.useruserinfo);
 						}
 #endif