If your not logged as admin, there is a batch_upload permission you may need to add to your users group.
- Size of the ZIP file? PHP default install limits uploads to 2Mb
- Image Gallery storage? Stock mysql limits to 1Mb per image in the my.cnf file
- LimitRequestBody restriction in the httpd.conf? or conf.d/ subfile?
Well thats a handful, its a config issue rather than a bug. as it works here. and on many of my own tiki sites here