--- a/vehicle.c	Sun Sep 09 20:52:54 2007 +0000
+++ b/vehicle.c	Sun Sep 09 22:35:21 2007 +0000
@@ -2633,7 +2633,7 @@
 	Vehicle *v;
 	StringID str;
 
-	if (!IsValidVehicleID(p1) || _cmd_text[0] == '\0') return CMD_ERROR;
+	if (!IsValidVehicleID(p1) || _cmd_text == NULL || _cmd_text[0] == '\0') return CMD_ERROR;
 
 	v = GetVehicle(p1);