There is no free version of Acrobat. What you are cry likely referring to
is the Adobe Reader. Adobe Reader only supports a very small subset of the
functionality describes in the Acrobat SDK. You need to read the SDK
documentation to understand what the limitations are. Chances are that you
need Adobe Acrobat for your sample program.
Karl Heinz Kremer
PDF Acrobatics Without a Net
PDF Software Development, Training and More...