Can u be a little more specific on the error your getting ???
Just in case :
1 -
2 - You click on the Download now link for the good version (Let's say u using XP)
3 - You click the Free button
4 - You wait for the ticket
5 - In the box you enter the 4 letters/numbers that are in the image just below the phrase : No Premium User. Please enter
And then u click Download via ... (Letters are case sensative)
Hope this can help u a bit