diff -Naur asterisk.old/channels/chan_vpb.c asterisk.new/channels/chan_vpb.c
--- asterisk.old/channels/chan_vpb.c    2005-08-31 10:20:36.000000000 +0200
+++ asterisk.new/channels/chan_vpb.c    2005-08-31 10:41:51.000000000 +0200
@@ -1926,8 +1926,8 @@
 
        if (!ast->tech || !ast->tech_pvt) {
                ast_log(LOG_WARNING, "%s: channel not connected?\n", ast->name);
-               res = ast_mutex_unlock(&p->lock);
 /*
+               res = ast_mutex_unlock(&p->lock);
                if (option_verbose > 3) ast_verbose("%s: unLOCKING in hangup [%d]\n", p->dev,res);
 */
                /* Free up ast dsp if we have one */