Config backups get zipped so if zipping isn't working the backup wizard won't work either.
The config is all stored in files -- no registry settings -- so you can back it up by hand if needed (see here).
Opus 9 64-bit uses a COM object/exe for zip support. If you have something blocking the exe (dopusx64.exe) or the main Opus process from talking to it (e.g. anti-virus/firewall or similar set to a very paranoid mode) then that could be what's going wrong.