"Is there more than one password?"
No, not all the parts require the password.
The first 4 parts are split .rar files (for example, 1.part1.rar & 1.part2.rar). To unpack a split rar file you must place all parts in the same folder, then when you open the first part, part1.rar, the second part, part2.rar, will be opened too.