>How much does it cost you and/or client to fix these issues? How much time do you waste when you have to stop what you're doing, change to the WinZip project, post a message, debug, analyze, fix, deploy, then try to get your attention back to what you were doing? Don't kid yourself that going with another tool would take longer or cost less. WinZip is nickel and diming you and/or client.
Changing the entire infrastructure in place for that would cost much more than a few hours trying to finalize that last issue. So, this is wiser to try this last option first before starting to change the entire world.