I humbly appreciate that. Can I ask if you overrode the files or merged them? I really feel as though I'm going mad...
I did not merge any files, I just uploaded the module files changing the name of my admin folder and changing the YOUR_TEMPLATE directories to all_business. Then I went into the zen cart admin customstomers--subscriptions and hit the install button. If I were you I would restore my backup and try the installation fresh.