Its not your fault, when I try to extract the files with the password, it says I need part 1 of the zip file even though I am starting with the 1st part. It also does bring up an error window saying part 1 of the zip file is corrupted.
Try to rename the zipped files onto same naming format as the part 1 of the zip file first before extracting them.
Part 1 is named zkr12.part01-K1SjqoI5.rar, so you need to rename the other files to zkr12.part02-K2SjqoI5.rar, zkr12.part03-K3SjqoI5.rar, and so on.