Anything that have to split up... (patch bigger than 200 MB), will have different file extension.
Then, you will see the file icon like that, since any files with Z01 (and other Z##) will not able to open by itself. Rather, you have to open via the file with ZIP extension as the leading file to unzip all parts.
Basically, just download IZArc
then unzip by click on the ZIP extension.
(If your ZIP utility can unzip by do the unzip/decompress option, that's also OK.)
Sincerely, Pan2011 ~ Pan2012 (May 19th, 2012)