I had a similar problem when for some reason Quicktime made itself the default viewer for TIF files. They all opened in Quicktime, which only showed the first page and was not annotatable. To fix, you open Quicktime, drill down through the preferences to a checkbox that designates Quicktime as the default TIF viewer. Uncheck it.
Open MS Document Imager, and drill down to a similar check box and check it, making Document Imager the default.
