Can you try to unzip the file manually in location that would be used, i.e.
C:\ProgramData\VMware\vSphere Web Client\vc-packages\vsphere-client-serenity\<your-package-id>-1.0.0
Unfortunately the ZipException doesn't give enough info on what went wrong.
Once you have your expanded package in the directory above (i.e. it contains plugin-package.xml and the plugins sub-directory with your war and jar files) you can login again, it won't try to install the zip again as the files are already there.