For digital signature to work with Reader, the document has to be Reader-enabled, either with Acrobat Pro (but not Standard) or LiveCycle Reader Extensions. In Acrobat 9 you'd select: Advanced > Extend Features in Adobe Reader
Classification: For internal use only
I truly appreciate your quick response. Are you able to point me to a location
where I can review the steps needed to make the PDF signable in reader if I
get Acrobat Pro?
If you get Acrobat 10, the menu item is: File > Save As > Reader Extended PDF > Enable Additional Features
Since Acrobat 11 will be available soon, here's the menu item for it: File > Save As Other > Reader Extended PDF > Enable More Tools (includes form fill-in & save)