Frickin PPTP Proxy

Connections to the target PPTP server are not being
completed.

frickin logs the following error in the message log:
Sent Call-Disconnect-Notify for invalid Call-ID = 64

frickin is being run on an OpenBSD 3.7 box with the
following relevant pf rules:

rdr on $IntIF inet proto tcp from any to any port pptp
-> 127.0.0.1 port pptp
rdr on $IntIF inet proto gre from any to any -> 127.0.0.1
pass out log quick on $ExtIF proto tcp from { $Self,
$Self2 } to any port = pptp keep state
pass in log quick on $IntIF proto tcp from any to any
port = pptp keep state
pass in log quick on $ExtIF proto gre from any to {
$Self, $Self2 }
pass out log quick on $ExtIF proto gre from { $Self,
$Self2 } to any
pass out log quick on $IntIF proto gre from { $Self,
$Self2 } to any
pass in log quick on $IntIF proto gre from any to any

There are some NAT rules, but they shouldn't be
affecting packets from frickin. Any suggestion as to
what could be causing the Call-ID error message and
failed connections?