Robb,
I downloaded and unzipped the test file with no problems using Winrar but Winzip 9.0 gives me an error message saying the zip file is corrupt.
Edit: I downloaded a Nolimits track from Coastercrazy.com and it unzipped and worked fine with Winzip 9.0 so I would say it is an issue with your webhost.
Rex 'Sic 'Em Robb!' Burrahm