We’ve upgraded the zip download in our web shares and web login, and it now creates ZIP64 archives (also sometimes referred to as version 4.5 archives). ZIP64 allows us to create archives with more than 65535 files and archives larger than 4GB.
Unfortunately, not all zip programs support ZIP64. Most notably, Windows XP’s Explorer does not support it. For Windows XP, we recommend using 7-Zip.
ZIP64 has been confirmed to work in OS X 10.6 Finder, Windows Vista/7 Explorer, and Ubuntu 8.10+ Archive Manager (a.k.a. File Roller). It is also supported by Info-Zip 6.0 on the multitude of platforms it supports.