nautilus-share / usershare cannot be used to make samba shares

[quequotion]

This is how the process should work:

1. Try to share a folder in nautilus.
2. Nautilus will ask permission to install samba and usershare dependencies.
3. Approve and install software
4. Folder is shared and available in the samba network.

This is what is happening.

1. Try to share a folder in nautilus.
2. Nautilus asks permission to install samba and useshare dependencies.
3. Approve and install software (occasionally this step fails due to an unrelated bug in apt, wherein all packages suddenly become "unsigned"; this step may also fail due to broken packages which try to overwrite each other, have broken install scripts, or are unavailable--in which case it may fail silently)
4. Everything falls apart. Sometimes usershare makes an error about changing a username i was never asked to supply into some kind of code, which seems to have been a bug that was fixed ages ago (or maybe not). Sometimes everything looks fine, but the folder isn't shared or available on the samba network; in fact most of the time my computer doesn't appear in the network at all, let alone its shares.

There are several workarounds available, but this needs to work out of the box.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: nautilus-share (not installed)
ProcVersionSignature: Ubuntu 3.5.0-8.8-generic 3.5.0
Uname: Linux 3.5.0-8-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.0.1-0ubuntu12
Architecture: amd64
Date: Tue Aug 21 13:43:53 2012
EcryptfsInUse: Yes
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Beta amd64 (20120407)
ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: nautilus-share
UpgradeStatus: No upgrade log present (probably fresh install)