This seems all due to the installer's insistance on finding a module called hamachi-update. I hope someone has a solution!
Maybe this will help someone in the future. Delete (or to be more conservative, rename it by appending an X to the key's name): HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Installer\Products\2F1C8FD962ED3D9409B931C2C3A5EC6B\SourceList
Thank you! While my key name wasn't 2F1C8..., finding it by looking for Hamachi on the right panel was no problem. After deleting the key I was able to reinstall succesfully. Thanks again.