Never allow 0 total pages.

web/root/msgs/msgs.ssjs

@@ -28,6 +28,8 @@ else {
 	template.can_delete=msg_area.sub[sub].is_operator;
 }
 var total_pages=Math.floor(msgarray.length/max_messages+(msgarray.length%max_messages?1:0));
+if(total_pages==0)
+	total_pages=1;
 var firstpage=0;
 var lastpage=firstpage+max_pages-1;
 if(lastpage>=total_pages)