The bottleneck in VPN connection

Can you post the output of your log while trying to establish a vpn connection at the debugging level? (in the asdm go to Monitoring -> Logging -> set logging level to debug in the drop down -> click view)

Also unless there is a compelling reason to stay at 7.2(4) I would upgrade to the latest 8.x release. The 7.2 series had some pretty major issues.

EDIT

That error means that the interface the incoming vpn is setup on doesn't have a crypto-map applied.

if you were following the instructions there, you probably applied the crypto map like this:

crypto map outside_map interface outside

if you are testing on the same lan you would need to do this:

crypto map outside_map interface inside

Ugly i know but it'll let you test, then remove from the inside interface and you are good to go.

If that doesn't work, would you be willing put post your running config?

EDIT 2:

Ok, lets simplify this config a little. Try disconnecting the XP machine from the ASA. And also remove the 192.168.1.1 ip address and DHCP pool from the ASA. Then try to connect via the vpn.

Your VPN connection uses MPPE encryption, but according to router's page http://www.draytek.co.uk/products/vigor2830.html - MPPE have no hardware support. Try to setup something else as encryption protocol (AES/DES/3DES). IMHO it is available only with L2TP protocol.