arn't you just renaming the .zip files into .nlpack, what makes them unable to read? You should unzip the .zip you download here. And them open the file inside.
What also could be is that you are opening the zip, double click the .nlpack and immediatly close the zip file. If you are doing that, then you are blocking the data, what the track packer is trying to get from the zip... If you want to close the zip file. Do it AFTER you've 'installed' the track...
Coastercount: 1410 (I've seen the world and it's horrid contraptions... @.@)
- Wood: 142
- Steel: 1268