well i dont know about copying maps 3 data over but i did fially get the nokia maploader to work the other day.

i used the old pc which is running windows XP and had my N900 in mass storage mode.

the first few times i tried it didnt recognise the phone, but after a few tries it connected it and downloaded the data.

it gave me options to choose different maps and also voices, so i downloaded the europe map and the english voices.
i now have maps version 1.01 on my phone.

what i dont understand is why it let me download voices, there dosent seem to be any option to use them in the updated maps version ?