Hello *,
I know that every one thinks that they found the problem with the web-zip download, but after reading all the posts related and making some tests on my own, because this happened to me too, I think that I found the problem.
It is not because of the file size (most cases are below 4GB), not because of links or file names in the archive, but because of the number of the files.
When it passes 65536 files it gives me this error:
2016-11-07 21:32:44: ERROR: Error while adding file “/opt/urbackup/user1/161107-1058/WinMent/DATA/AQERT/2013_08/DISTRIB.XG0” to ZIP file. RC=0
2016-11-07 21:32:44: ERROR: Error while adding file “/opt/urbackup/user1/161107-1058/WinMent/DATA/AQERT/2013_09” to ZIP file. RC=0
2016-11-07 21:32:44: ERROR: Error while adding files and folders to ZIP archive
The folder “/opt/urbackup/user1/161107-1058/WinMent/DATA/AQERT/2013_08/” does contain more files after DISTRIB.XG0 but it stops at this one (because this is file number 64k in the archive) , it tries the next subfolder … without luck, and after that exits with corrupted archive.
The error can happen on other folders to, but it stops every time at the file with number 64k.
I use the latest version 2.0.36 but the problem is still there.
Uroni … please help us. 
Thank you