This has been uploaded to Desura and released.
I'm pretty sure a lot of the errors in V17.6 are caused by the archiving system we're using to reduce the file count in the auto-updater version. This explains why the standalone build is much more stable, and why Matthew didn't notice any of the obvious bugs when testing (as he tested the standalone version, which doesn't have the archiving).
This is a small update (approx 1.5mb) but I think it should fix the issues in the auto-updater version when it is approved - a couple of test missions suggests that it does.
If you already have the standalone, you won't need this hotfix.