If you go in the Administrative console (http://localhost:8080/adminui) under Services/LiveCycle PDF Generator ES/Create PDF, can you convert your tiff to a PDF using that interface?
I have a very similar problem... I try and convert a Word document to PDF in the Services / Livecycle PDF Generator ES / Create PDF screen and receive:
Error Code:80012
Error Message: ALC-PDG-080-012-This operation requires GeneratePDF service to be installed.
Any help on how I can install this service would be greatly appreciated