Outbound PPTP VPN connection through Cisco 2821

Hi Experts,

Apologies if this topic has been covered many times before, however I need input for my particular configuration.

I am setting up a replacement for our currently ADSL connection.  We have a Cisco 2811 provided by the new ISP which comes preconfigured with no access to the device.  Because we are prohibited from touching the configuration of this device, we are using a Cisco 2821 connected to the 2811 with cat5 (Interface gig0/1).

Below is the current router configuration so far, all seems well (can browse the web etc), but I notice we cannot establish VPN connections outbound, via PPTP.  I can telnet to the VPN servers on 1723, but Windows times out at verifying username/password.

I guess this is something to do with GRE, but the config looks good to me, any ideas?

Building configuration...

Current configuration : 3701 bytes
!
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
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hostname C2800
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boot-start-marker
boot-end-marker
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logging message-counter syslog
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no aaa new-model
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dot11 syslog
ip auth-proxy max-nodata-conns 3
ip admission max-nodata-conns 3
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ip cef
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!
ip domain name syn.local
ip name-server 192.168.50.10
ip inspect name firewall tcp
ip inspect name firewall udp
ip inspect name firewall icmp
ip inspect name firewall pptp
no ipv6 cef
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multilink bundle-name authenticated
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voice-card 0
 no dspfarm
!
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!
username xxxxxxxxxxxxxxxxxxxxxx
username xxxxxxxxxxxxxxxxxxxxxx
archive
 log config
  hidekeys
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crypto isakmp policy 1
 encr 3des
 authentication pre-share
 group 2
crypto isakmp key xxxxxxxxxxxxxxxxxxxxxx address xxxxxxxxxxxxxxxxxxxxxx
!
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crypto ipsec transform-set ESP-3DES-SHA esp-3des esp-sha-hmac 
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crypto map SDM_CMAP_1 1 ipsec-isakmp 
 description ART
 set peer xxxxxxxxxxxxxxxxxxxxxx
 set transform-set ESP-3DES-SHA 
 match address 103
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interface Tunnel1
 description Link to ART
 ip address 10.1.2.1 255.255.255.252
 ip mtu 1472
 keepalive 10 3
 tunnel source GigabitEthernet0/1
 tunnel destination xxxxxxxxxxxxxxxxxxxxxx
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interface GigabitEthernet0/0
 no ip address
 duplex auto
 speed auto
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interface GigabitEthernet0/0.1
 encapsulation dot1Q 1 native
 ip address 192.168.51.253 255.255.255.0
 ip nat inside
 ip virtual-reassembly
!
interface GigabitEthernet0/0.2
 encapsulation dot1Q 2
 ip address 192.168.50.253 255.255.255.0
 ip nat inside
 ip virtual-reassembly
!
interface GigabitEthernet0/1
 ip address 77.89.162.98 255.255.255.240
 ip access-group 102 in
 ip nat outside
 ip inspect firewall in
 ip inspect firewall out
 ip virtual-reassembly
 duplex auto
 speed auto
!
ip forward-protocol nd
ip route 0.0.0.0 0.0.0.0 GigabitEthernet0/1
ip route 10.0.0.0 255.255.255.0 10.1.2.2
ip route 192.168.1.0 255.255.255.0 192.168.50.254
ip route 192.168.48.0 255.255.240.0 192.168.50.254
no ip http server
no ip http secure-server
!
!
ip nat inside source list 1 pool synnatpool overload
ip nat inside source list 2 pool t2natpool overload
ip nat inside source route-map rmap_1 interface GigabitEthernet0/1 overload
ip nat inside source static 192.168.50.14 77.89.162.104
!
access-list 1 permit 192.168.50.0 0.0.0.255
access-list 2 permit 192.168.51.0 0.0.0.255
access-list 101 deny   ip 192.168.50.0 0.0.0.255 192.168.52.0 0.0.0.255
access-list 101 deny   ip 192.168.50.0 0.0.0.255 192.168.53.0 0.0.0.255
access-list 101 deny   ip 192.168.50.0 0.0.0.255 192.168.54.0 0.0.0.255
access-list 101 deny   ip 192.168.50.0 0.0.0.255 192.168.55.0 0.0.0.255
access-list 101 deny   ip 192.168.50.0 0.0.0.255 192.168.56.0 0.0.0.255
access-list 101 deny   ip 192.168.50.0 0.0.0.255 192.168.57.0 0.0.0.255
access-list 101 deny   ip 192.168.50.0 0.0.0.255 192.168.58.0 0.0.0.255
access-list 101 deny   ip 192.168.50.0 0.0.0.255 192.168.59.0 0.0.0.255
access-list 101 deny   ip 192.168.50.0 0.0.0.255 192.168.246.0 0.0.0.255
access-list 101 permit ip 192.168.50.0 0.0.0.255 any
access-list 101 permit ip 192.168.51.0 0.0.0.255 any
access-list 102 permit tcp 207.126.144.0 0.0.15.255 any eq smtp
access-list 102 permit tcp any any established
access-list 102 permit gre any any
access-list 102 permit icmp any any
access-list 102 permit udp any any
access-list 103 permit ip 192.168.50.0 0.0.0.255 10.0.0.0 0.0.0.255
!
!
!
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route-map rmap_1 permit 1
 match ip address 101
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control-plane
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line con 0
line aux 0
line vty 0 4
 login local
 transport input ssh
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scheduler allocate 20000 1000
end