You most likely ended up here looking for the Zip Uploader extension for WP E-Commerce. If that’s the case, please note that unfortunately with the release of WPEC 3.8 in 2011, I had to discontinue the Zip Uploader as it was no longer compatible. Unfortunately the code differences were so large that it’s not even worth sharing the old code. I don’t have any current plans to bring it back.
All the best!