SE Z800i "Cant load map: null" IO Error

I successfully installed navigami on my Sony Ericsson Z800i using bluetooth. I am trying to donwload maps using Serial Proxy (over bluetooth), but i am getting the following error.

IO Error
Can't load map:
null

Also please clarify the following...

1. How to know that my phone is connected to internet through the navigami-->bluetooth-->Computer ?
2. Which area map will get downloaded. Do i have option to select map location?

Thanks a lot for the efforts you are putting..

-Satish

bt connection

1. You should see it in your bt driver.I try to add some function to see it.
2. go to menu>map>manage maps a you will see your coordinates. you can move and zoom the map and actual map tile will be downloaded.