Unknown error: '<class 'KeyError'>' ("The cache has no package named wine-staging-i386")

I got the same error in 14.04. Re-installation of wine-staging-i386 package fixed the problem:

sudo apt-get install --reinstall wine-staging-i386

If you're running Ubuntu 64 bit then the problem is likely due to the fact that "wine-staging-amd64" depends on "wine-staging-i386" which is a virtual package and not actually installable. From what I can deduce from reading about this here "the cache has no package" error when wine update is available is that the build environment or updater isn't dealing with the multiarch nature of this "wine" install.

If you're not using the pipelight experimental 64bit flash or unity3d plugins and don't require the 64bit version of "wine-staging" for anything else, then you could always remove "wine-staging-amd64" and it's dependencies. If this is what you want to do then make sure to disable any 64 bit plugins you have enabled/loaded in pipelight first as follows:

pipelight-plugin --disable x64-flash

and/or

pipelight-plugin --disable x64-unity3d

Note: You may need to use "sudo" at the start of those if you installed the 64 bit plugins for all users.

Then proceed with uninstalling the 64 bit version of "wine-staging" as follows:

sudo aptitude -V purge wine-staging wine-staging-amd64 wine-staging:i386+

This will uninstall "wine-staging" (64 bit) dependancy package and "wine-staging-amd64" (64 bit) and install "wine-staging:i386" (32 bit) dependancy package.

The 32 bit package depends on only 32 bit so don't have a problem as far as I can tell so far.

Note: YMMV ;)